The aim of the present study was to determine the effect of pesticides on the plasma levels of amino acids and serum liver enzymes in farm workers in the United Arab Emirates. This case-control study consisted of 103 farm workers (case) and 105 non-farm workers (control), matched for age, sex, and nationality selected from Al-Ain City, Dubai, Sharjah, and Fujairah Emirates. The Indian-subcontinent workers represented the majority among farmers (90.3%) and non-farmers (82.9%). Seventy percent of the subjects reported working in a field with an obvious chemical smell and 60% of the farm workers reported mixing pesticides and spraying with chemical pesticides. Amino acid analysis showed higher values among farmers than non-farmers for histidine, threonine, lysine, and arginine as essential amino acids (p<0.0001). Ornithine, taurine, glutamic, serine glycine, and tryptophan as non-essential amino acids showed significantly higher values in farmers when compared with the non-farmers (p<0.0001). (C) 1999 Elsevier Science Ltd.