Leachate is the aqueous effluent generated as a consequence of rainwater percolation through wastes and the inherent water content of wastes themselves. Its quality is the result of biological, chemical and physical processes in landfills combined with the specific waste composition and the landfill water regime. In Khulna city, municipal solid waste is dumped in the Rajbandh landfill site where large amount of leachate is produced every day. This leachate is pretreated by anaerobic process in a pond and pumped out to the surface water from three wells. This pretreated leachate has great impact on surrounding surface water and environment. The aims of this study are to asses and evaluate the environmental impact of the pretreated leachate. In order to do this, some parameters including pH, BOD, COD, Iron content, Alkalinity, TC etc. of the collected leachate and surface water are determined. Obtained values of the parameters are compared with the standard value. Amount of green house gas emission and their effects on human health are also determined and reviewed. Therefore, this paper provides insight regarding how the leachate puts impact to the environment.