The landfill leachates were acidified to pH 3, filtered to remove the humic acid ppts., treated with H(2)O(2)/Fe(II) mixts. for 15-480 min (a modified Fenton process), neutralized with NaOH (to pH 8.5), let for sedimentation for 1 h and finally analyzed for BOD(5), COD and H(2)O(2) content. The treatment resulted in a decrease in BOD(5) and COD after 480 min by 91.5% and 90.6%, resp. The process efficiency was higher than those achieved in described O(3)/H(2)O(2) and H(2)O(2)/UV processes. The optimum dose of H(2)O(2)/Fe(II) was found as 3000/500 mg/L. After 240 min of Fenton reaction and addnl. biolog. treatment, the COD and BOD(5) values were reduced by around 97%. A no. of org. compds. were identified by GC-MS in raw and treated leachates.