It earned $6.9bn (34.5bn) in the second quarter, down from $15.9bn in 2012.
Chairman Rex Tillerson said the figures showed “continued strong operational performance and investments”.
Shares in Exxon Mobil fell by $1.65, or 2%, to $92.08 after the results were published.
Exxon had been boosted in the second quarter last year by the sale of a Japanese lubricants division and other assets. Taking away those gains, Exxon’s net income fell this year by 19%.
The company last posted earnings of less than $7bn the first quarter of 2010.
Exxon said production of oil and gas fell by 1.9% in the quarter, making it the ninth straight quarter production had fallen compared with the year earlier.