The process of pesticide (gamma -HCH and inactive isomers alpha- and beta -HCH, DDT, DMDT, fenitrothion and chlorfenvinphos) removal from industrial wastewater using Fenton's reaction has been analysed. Most of the pesticides were completely degraded at H2O2 Concentration of 2.5 g/dm(3); however, only at 5 g/dm(3) were all the examined pesticides completely removed and the results repeatable. The most effective process was for fenitrothion (from 98.5 to 100%) and chlorfenvinphos (from 97.1 to 100%), whereas organochlorine pesticides were removed with efficiency of more than 90%. The optimum ratio of [Fe2+] to [H2O2] was from 1:3 to 1:2 while the optimum pH was from 3.0 to 3.5. Tests based upon a bioluminescent bacteria Vibrio fischeri NRRL B-11177, at optimized Fenton's reaction parameters, show the reduction of toxicity to non-toxic levels.