Pesticide residues in human adipose tissue and liver tissue samples were identified by mass spectrometry coupled with gas chromatography. An extensive extraction and cleanup procedure was adapted from existing analytical methods to separate pesticide residues from the tissue samples. Concentration of pesticides in tissue ranged from 0.073 to 28.7 ppm. Mass spectral data were computer-enhanced to identify heptachlor epoxide. Other pesticides confirmed included the beta-isomer of 1,2,3,4,5,6-hexachlorocyclohexane (HCH), several isomers and metabolites of p,p'-DDT, and dieldrin. Advantages, limitations, and suggested modifications for improving the combined gas chromatography-mass spectrometry technique for pesticide residue analysis are discussed.