Greenhouse tomato samples (n = 20) was analyzed before and after peel removal in order to determine surface auxin residue. Mean 4-CPA residue levels of greenhouse tomatoes with and without peels were 0.383 +/-0.123 mg kg(-1) and 0.241 +/-0.085 mg kg(-1), respectively. This difference (36 +/- 13%) was statistically significant. ne frequency distribution curve of tomatoes with peel had a peak point at 4-CPA reside interval of 0.4-<0.5 mg kg(-1) tomato, and shifted back to 4-CPA residue interval of 0.2-<0.3 mg kg(-1) for tomatoes without peel. Percentage of samples having 4-CPA level lower than the critical concentration of 0.5 mg kg(-1) was 80% before peel removal, but increased to 100% upon being peeled. ne mean 4-CPA residue of peels was roughly estimated to be 3.449 mg kg(-1) peel based on peeled versus nonpeeled fruit residue.