Exhibit 99.1

Calgary, July 28, 2011

Imperial Oil announces estimated second quarter financial and operating results

Bruce March, chairman, president and chief executive officer of Imperial Oil, commented:

“Imperial’s earnings in the second quarter of 2011 were $726 million, up 40 percent or $209 million from 2010. The Upstream business was the primary contributor to this increase with strong earnings driven in part by higher production from our Cold Lake operations, which set another production record in the quarter. Overall, Upstream results were very good despite challenges in delivering conventional crude oil volumes from our Norman Wells operations as a result of third-party pipeline reliability issues in the quarter. I am especially pleased at how the organization continues to sustain base business operating performance while executing a complex portfolio of projects, including the Kearl oil sands project.

Our Downstream business continued to contribute solid results despite significant planned refinery maintenance activity, which impacted our second quarter results by about $95 million. Operations excellence remains a key focus for our Downstream business. Our Chemical segment performed very well with strong operations, sales, and margins contributing to another quarter of good earnings.

Imperial’s consistent, long-term and disciplined business approach has allowed us to continue to advance our growth plans for the company while sustaining focus and performance in our base business. Capital and exploration expenditures to the end of June were $1,784 million mostly directed to the continued development of the Kearl project. In addition to capital spending for Kearl, we continue to progress activity at Cold Lake, including the Nabiye project, and the production pilot at Horn River. Our continued strong business performance allowed us to finance these investments largely by cash flow from operations.”

Imperial Oil is one of Canada’s largest corporations and a leading member of the country’s petroleum industry. The company is a major producer of crude oil and natural gas, Canada’s largest petroleum refiner, a key petrochemical producer and a leading marketer with a coast-to-coast supply network that includes about 1,850 retail service stations.

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Second quarter items of interest

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Second quarter 2011 vs. second quarter 2010

The company’s net income for the second quarter of 2011 was $726 million or $0.85 a share on a diluted basis, compared with $517 million or $0.60 a share for the same period last year.

Earnings in the second quarter were higher than the same quarter in 2010 primarily due to the impacts of higher crude oil commodity prices of about $430 million, stronger industry refining margins of about $80 million and increased Cold Lake bitumen production of about $70 million. These factors were partially offset by the unfavourable effects of higher royalty costs of about $120 million, lower Syncrude volumes of about $50 million, primarily a result of higher unplanned maintenance activities, and lower conventional crude oil volumes of about $45 million due to third-party pipeline reliability issues. Earnings were also negatively impacted by the foreign exchange effects of the stronger Canadian dollar of about $70 million and higher planned refinery maintenance activities of about $40 million. Second quarter 2010 earnings included a gain of about $25 million from the sale of non-operating assets.

Upstream net income in the second quarter was $624 million, $178 million higher than the same period of 2010. Earnings benefited from higher crude oil commodity prices of about $430 million and increased Cold Lake bitumen production of about $70 million. These factors were partially offset by lower Syncrude volumes of about $50 million, primarily a result of higher unplanned maintenance activities, and lower conventional crude oil volumes of about $45 million due to third-party pipeline reliability issues. Earnings were also negatively impacted by higher royalty costs due to higher commodity prices of about $120 million and the foreign exchange effects of the stronger Canadian dollar of about $55 million.

The average price of Brent crude oil in U.S. dollars, a common benchmark for Atlantic Basin oil markets, was $117.33 a barrel in the second quarter of 2011, up about 50 percent from the corresponding period last year. The average price of West Texas Intermediate (WTI) crude oil in U.S. dollars, a common benchmark for mid-continent North American oil markets, was $102.34 a barrel in the second quarter, up about 31 percent from the corresponding period last year. The company’s average realizations on sales of Canadian conventional crude oil and synthetic crude oil increased accordingly. The company’s average bitumen realizations in the second quarter were about 26 percent higher than that in the corresponding period of 2010, more in line with the continuing weakness in WTI crude oil markets.

Gross production of Cold Lake bitumen during the second quarter averaged 158 thousand barrels a day, a second-quarter record, up from 140 thousand barrels in the same quarter last year. Increased volumes were due to contributions from new wells steamed in 2010 and 2011 and the cyclic nature of production at Cold Lake.

The company’s share of Syncrude’s gross production in the second quarter was 70 thousand barrels a day, versus 81 thousand barrels in the second quarter of 2010. Lower production was primarily the result of higher unplanned maintenance activities and the negative impact of wild fires in northern Alberta on the Syncrude operations.

Gross production of conventional crude oil averaged 16 thousand barrels a day in the second quarter, down from 24 thousand barrels in the second quarter of 2010. Lower volumes were primarily due to the third-party pipeline unplanned downtime which caused significantly reduced production at the Norman Wells field. This pipeline downtime carried forward into the third quarter.

Gross production of natural gas during the second quarter of 2011 was 257 million cubic feet a day, down from 289 million cubic feet in the same period last year. The lower production volume was primarily a result of natural reservoir decline.

Downstream net income was $64 million in the second quarter of 2011, compared with $68 million in the same period a year ago. Second quarter earnings in 2010 included a gain of about $25 million from sale of non-operating assets. Impacting earnings in the second quarter of 2011 when compared to the prior year’s second quarter were higher planned refinery maintenance activities totalling about $40 million.

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Second quarter 2011 vs. second quarter 2010 (continued)

Unfavourable effects of the stronger Canadian dollar were about $15 million. Offsetting these negative factors was the favourable impact of stronger industry refining margins of about $80 million in the quarter. Planned refinery maintenance activity impacted second quarter 2011 results by about $95 million.

Chemical net income was $36 million in the second quarter, $14 million higher than the same quarter last year. Higher polyethylene and intermediate products sales volumes and lower costs due to lower planned maintenance activities were the main contributors to the increase.

Net income effects from Corporate and other were $2 million in the second quarter, compared with negative $19 million in the same period of 2010. Favourable effects were primarily due to lower share-based compensation charges.

Cash flow generated from operating activities was $656 million during the second quarter of 2011, compared with $324 million in the same period last year. Higher cash flow was primarily driven by higher earnings and working capital effects.

Investing activities used net cash of $893 million in the second quarter, an increase of $96 million from the corresponding period in 2010. Additions to property, plant and equipment were $903 million in the second quarter, compared with $851 million during the same quarter 2010. Expenditures during the quarter were primarily directed towards the advancement of the Kearl oil sands project. Other investments included development drilling and advancing the Nabiye expansion project at Cold Lake, environmental and other projects at Syncrude, as well as exploration drilling and the advancement of the production pilot at Horn River.

In the second quarter, the company increased its long-term debt level by $320 million by drawing on an existing facility and issued additional commercial paper which increased short-term debt by $135 million.

The company’s cash balance was $419 million at June 30, 2011, up $152 million from $267 million at the end of 2010.

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Six months highlights

Six months 2011 vs. six months 2010

Net income for the first six months of 2011 was $1,507 million or $1.76 a share on a diluted basis, versus $993 million or $1.16 a share for the first half of 2010.

For the six months, increased earnings were primarily attributable to higher crude oil commodity prices of about $460 million, stronger industry refining margins of about $255 million and increased Cold Lake bitumen production of about $100 million. These factors were partially offset by the unfavourable effects of the stronger Canadian dollar of about $140 million, higher royalty costs of about $130 million and lower conventional crude oil volumes of about $45 million due to third party pipeline issues.

Upstream net income for the six months of 2011 was $1,152 million, up $262 million from 2010. Earnings increased primarily due to the impacts of higher crude oil commodity prices of about $460 million and increased Cold Lake bitumen production of about $100 million. These factors were partially offset by the unfavourable effects of higher royalty costs of about $130 million, the stronger Canadian dollar of about $105 million and lower conventional crude oil volumes of about $45 million as a result of the second quarter 2011 third-party pipeline issues.

The average price of Brent crude oil in U.S. dollars, a common benchmark for Atlantic Basin oil markets, was $111.20 a barrel in the six months of 2011, up about 44 percent from the corresponding period last year. The average price of West Texas Intermediate (WTI) crude oil in U.S. dollars, a common benchmark for mid-continent North American oil markets, was $98.50 a barrel in the six months of 2011, up about 26 percent from the corresponding period last year. The company’s average realizations on sales of Canadian conventional crude oil and synthetic crude oil increased accordingly. The company’s average bitumen realizations in the first six months of 2011 were about six percent higher than that in the corresponding period of 2010. Cold Lake bitumen realizations were negatively impacted by third-party pipeline integrity issues carried over from the second half of 2010 into the first quarter of 2011 and continued weakness in WTI crude oil markets.

Gross production of Cold Lake bitumen for the six months was 157 thousand barrels a day this year, a first six-month record, compared with 144 thousand barrels in the same period of 2010. Increased volumes were due to contributions from new wells steamed in 2010 and 2011 and the cyclic nature of production at Cold Lake.

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Six months 2011 vs. six months 2010 (continued)

The company’s share of gross production from Syncrude averaged 75 thousand barrels a day, up slightly from 74 thousand barrels in 2010. Increased production was due to improved operating reliability.

Gross production of conventional crude oil was 19 thousand barrels a day, compared with 24 thousand barrels in 2010. Lower volumes were primarily due to third-party pipeline downtime, which reduced production at the Norman Wells field, and natural reservoir decline.

Gross production of natural gas during the six months of 2011 was 263 million cubic feet a day, down from 281 million cubic feet in the six months of 2010. The lower production volume was primarily a result of natural reservoir decline.

Six months Downstream net income was $340 million, an increase of $233 million over 2010. Higher earnings were primarily due to favourable impacts of stronger industry refining margins of about $255 million and $40 million associated with improved refinery operations. These factors were partially offset by the unfavourable impact of the stronger Canadian dollar of about $35 million. Earnings in 2010 included a gain of about $25 million from sale of non-operating assets.

Chemical net income in the first half of 2011 was $74 million, up $53 million from 2010. Earnings were positively impacted by improved industry margins across all product channels, lower costs due to lower planned maintenance activities and higher polyethylene sales volumes.

For the six months of 2011, net income effects from Corporate and other were negative $59 million, versus negative $25 million last year. Unfavourable effects were primarily due to changes in share-based compensation charges.

Key financial and operating data follow.

Forward-Looking Statements

Statements in this report relating to future plans, projections, events or conditions are forward-looking statements. Actual future results, including project plans, costs, timing and capacities; financing sources; the resolution of contingencies and uncertain tax positions; the effect of changes in prices and other market conditions; and environmental and capital expenditures could differ materially depending on a number of factors, such as the outcome of commercial negotiations; changes in the supply of and demand for crude oil, natural gas, and petroleum and petrochemical products; political or regulatory events; and other factors discussed in Item 1A of the company’s 2010 Form 10K.

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Attachment I

IMPERIAL OIL LIMITED

SECOND QUARTER 2011

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Attachment II

IMPERIAL OIL LIMITED

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Attachment III

IMPERIAL OIL LIMITED

SECOND QUARTER 2011

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Attachment IV

IMPERIAL OIL LIMITED

SECOND QUARTER 2011

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Attachment V

IMPERIAL OIL LIMITED

SECOND QUARTER 2011

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