An LC–DAD method was developed to determine residues of oxamyl on greenhouse workers’ skin. The wipe test was used to obtain samples from hands, forearms, neck and gloves of workers taking cactus cuttings 48 h after pesticide treatment. It was validated in a concentration range 50–5,000 ng mL−1. The results on six workers and ten office employees indicated significant differences particularly in the hand samples. To avoid the overestimation owing to an interfering substance we proceeded to confirm these findings with LC–MS–MS, which found the pesticide only on the surface of the workers’ gloves, proving that there was indeed some UV interference.