The company announced plans to sell the refinery and related supply terminals to prospective buyers in the coming months.
The decision forms part of a review where other options include the Dartmouth facility being converted to a terminal, including other alternatives.
Imperial Oil chairman, president and CEO Bruce March said this is a difficult decision.
"We hope to make a decision about the sale or other alternatives by first quarter 2013 depending on the response to marketing efforts," added March.
"In the meantime, safe, reliable, environmentally responsible operations remain our key focus.
Imperial Oil cited the move is led by the decline in demand for refined products in the highly-competitive Atlantic basin in recent years, due to significant global competition.
The company also stated that the refinery has not met expected financial returns.
The refinery, commissioned in 1918, has a capacity of 88,000 barrels per day and produces a wide range of petroleum products including gasoline, diesel, jet fuel, home heating fuel, marine fuel, heavy fuel oil and asphalt.
Approximately 200 employees and 200 contractors work at the refinery and related terminals in Dartmouth and Sydney, Corner Brook, Sept-Iles, and Cap aux Meules in the Magdalen Islands.
