An analytical method for the determination of 2-methyl-4-chlorophenoxybutyric acid (MCPB) and its primary metabolite 2-methyl-4-chlorophenoxyacetic acid (MCPA) residues in peas was developed utilizing liquid-liquid partitioning, derivatization of acids with diazomethane, Florisil® column cleanup, and gas chromatography/mass spectrometry. Method validation recoveries from various pea matrixes (peas without pods, peas with pods, and dry peas) ranged from 69-108% for MCPB and 60-94% for MCPA, over four levels of fortification (0.01, 0.10, 0.50, and 1.0 ppm) . Control and MCPB-treated pea samples collected from six IR-4 (USDA, Interregional Research Project No. 4, Minor Use Pesticide Registration Program) field sites had residue levels less than 0.01 ppm, except for one that had 0.017 ppm. The method was validated down to the limit of quantitation at 0.01 ppm and to the limit of detection at 0.0045 ppm.