A semiquantitative capillary column gas chromatographic method is described for the determination of diesel fuel contamination in various canned seafood products. The diesel contaminants are separated from the fish sample by steam distillation, with little carry-over of interfering intrinsic materials such as fish oils. The diesel fuel is extracted from the condensate with n-hexane, and the extract is analyzed on an SPB-1 fused silica capillary column. The efficiency of recovery of diesel fuel added to canned seafood at levels of 40-400 ppt ranged from 72 to 102%. With the additional step of concentrating the hexane extract, the sensitivity of this procedure may be increased at least 10-fold. This procedure can detect the differences among diesel fuel grades No. 1, 2, and 5, and variations within diesel grade No. 2, and thus may be useful in determining the type of petroleum contaminants present in various canned fish products.