Bioremediation of soil contaminated with pesticides g-HCH (lindane), DDT and p,p'-DMDT (methoxychlor) has been studied in batch tests. The treatments included different combinations of the following amendments: carbon source, reducing agent, zero-valent iron, surfactant and anaerobic biomass (methanogenic granular sludge or fermented sewage sludge). The tests seeded with both types of anaerobic biomass showed high removal of all pesticides. DDT was transformed into DDD, but accumulation of this metabolite was considerably lower than that resulting from stoichiometric reaction. Addition of a surfactant together with anaerobic biomass further enhanced the effectiveness of the process.