The effect of some pesticides on alkaline phosphatase (ALK-P) (E.C 22.214.171.124), Amylase (E.C. 126.96.36.199) creatine kinase (CK) (E.C. 188.8.131.52), delta-glutamyltransferase (GGT-P) (E.C. 184.108.40.206) and lactate dehydrogenase (LDH) (E.C. 220.127.116.11) were investigated. These pesticides were baytroid [Cyano-(4-fluoro-3-phenoxyphenyl)-methly-3-(2,2-dichloroethenly)-2,2-dimetylcyclopropancarboxylate], imperator [cyano-3-phenoxy-benzyl-cis,trans-3-(2,2-dichloroethenyl)-2,2- dimetylcyclopropancarboxylate]. Meothrin [cyanophenoxybenzyl- 2,2, 3,3-tetramethyl cyclopropanecarboxylate], Sumicidin [cyano-3-phenoxybenzylcyclopropane carboxylate] T C A (trichloroacetic acid) and talstar. ISO values of chemicals caused inhibition were determined by means of activity percentage [I] diagrams. Pesticides having the strongest inhibitory effects on each enzyme were found to be talstar (I-50 = 7,3 x 10(-4) M) for ALK-P; talstar (I-50) = 7,1 x 10(-4) M) and baytroid (I-50 = 8.8 x 10(-4) M) For amylase; baytroid (I-50 = 1,25 x 10(-4) M) for CK. baytroid (I-50 = 8.8 x 10(-4) M and I-50 = 9,7 x 10(-4) M) for GGT-P and LDH. Baytroid and talstar In general caused a high inhibition for all enzymes. pollutants such as TCA, meothrin, imparator, sumicidin weakly inhibed each enzymes.