This paper presents the results of a treatability study conducted on highly contaminated wastewater using Fenton reaction at neutral pH, in the presence of humic substances. It has been found that addition of hurmates significantly accelerates the degradation of cyanide, thiocyanide, phenols and arsenic by ferrous iron and hydrogen peroxide. Only negligible amounts of contaminants of concern were removed when humates were added without the Fenton reagent. The mechanism of the humates effect is discussed. It is suggested that the combination of Fenton reagent with humates could provide a convenient and economical way for treatment of highly contaminated water at neutral pH.