This study presents the efficiency of Fenton process in the degradation of organic compounds of nuclear laundry water. The influence of Fe2+ and hydrogen peroxide ratio, hydrogen peroxide dose, pH and treatment time were investigated. The degradation of non-ionic surfactant and other organic compounds was analysed as COD, TOC and molecular weight distribution (MWD). The most cost-effective degradation conditions were at H2O2/Fe2+ stoichiometric molar ratio of 2 with 5 min mixing and H2O2 dose of 1000 mg l(-1). With the initial pH of 6. the reductions of COD and TOC were 85% and 69%, respectively. However, the removal of the organic compounds was mainly carried out by Fenton-based Fe3+ coagulation rather than Fenton oxidation. Fenton process proved to be much more efficient than previously performed ozone-based oxidation processes. (C) 2008 Elsevier B.V. All rights reserved.