Shares edged down about 1 percent to $44.30 in trading before the market open.
Net profit in the second quarter was $1.3 billion, or 87 cents per share, compared with $5.44 billion, or $3.50 per share a year earlier.
Analysts on average had expected a profit of 86 cents per share, according to Reuters Estimates.
Conoco's daily oil and gas output, excluding their 20 percent interest in Russian oil major Lukoil
(Reporting by Anna Driver in Houston, editing by Maureen Bavdek)