This study assessed the concentration of pesticides residue in an agriculturally endemic basin in southeastern Nigeria, where pesticide is freely used without any form of regulations. Analysis of water and fish from the streams and tributaries in the basin reveal a very high level of pollution from organochloride pesticides and atrazine which occur above international drinking water standards and at health hazard levels where ecosystem and human health can be compromised. Some of these chemicals have been outrightly banned or their use restricted by international conventions, yet they are freely used in the study area. There is therefore a need for Nigeria to adhere to the provisions of the Stockholm Convention and the earlier Rotterdam Convention which list more chemicals for various forms of restriction to protect man and the environment.