Normal and misshapen greenhouse-grown tomatoes (n=100 for each group) were analyzed separately in order to compare their synthetic auxin residue contents. Sharply elongated blossom-ends, "hook-like" and "slice-like" deformations were the auxin-induced shape abnormalities most often observed. The greenhouse tomatoes were found to contain only 4-chlorophenoxyacetic acid (4-CPA), but no 2,4-dichlorophenoxyacetic acid (2,4,D) or beta-naphtoxyacetic acid (BNOA) residues. Seasonal variations in the mean 4-CPA residues of greenhouse tomatoes were significant (p<0.05) through 1991-97. Mean 4-CPA residues of normal and misshapen greenhouse tomatoes were 0.323+/-0.187 mg kg(-1) and 0.363+/-0.150 mg kg(-1), respectively. The difference was not statistically significant (p>0.05). The average 4-CPA residue in abnormally shaped fruit is greater than 0.3 mg kg(-1). While misshapen fruit always contained residues of at least 0.1 mg kg(-1), 95% of normal-shaped fruit also contained residues exceeding 0.1 mg/kg(-1).