In order to determine if Blue Crabs (Callinectes sapidus) can bioaccumulate and retain complex mixtures of petroleum hydrocarbons, adult crabs were exposed for 14 days or 30-35 days in continuous flow-through seawater systems to three sublethal concentrations, nominally 0.00 (control), 0.01, or 1.0 ppm (mg/liter), of the water-accomodated fraction (WAF) of Number (No.) 2 fuel oil. Crabs exposed for 14 days were subsequently exposed to clean running seawater for a 30 day 'depuration' period. Gill, hepatopancreas, and muscle tissue samples were collected from control, WAF exposed, and 'depurated' crabs and analyzed by gas chromatography and/or gas chomatography-mass spectrometry. No. 2 fuel oil compounds were not detected in any of the tissues of the control crabs. Trace amounts of fuel oil compounds were detected in gill and hepatopancreas tissues collected from crabs exposed to the 0.01 ppm WAF and no fuel oil compounds were detected in muscle tissues. All tissues of crabs exposed to the 1.0 ppm WAF accumulated No. 2 fuel oil compounds and considerable amounts remained in hepatopancreas and gill tissues following depuration for 30 days in clean seawater.