In this study the first measurements of chlorinated pesticide pollution in the Northeast region of Brazil are reported. Water samples collected at 28 stations along the Ipojuca river, during both the dry and rainy seasons, were analysed for 18 common organochlorine pesticides. Residues were extracted in n-hexane, cleaned up with Florisil column and then quantitatively analysed by gas chromatography. Heptachlor and HCH residues, at levels as high as 50 and 4 µg l−1, respectively, were detected in almost half these samples. Additionally low levels of aldrin, DDT, chlordane and endrin were also found in samples collected adjacent to highly populated areas. The presence of these chlorinated insecticides in the environment may, possibly, be ascribed to the side effects of public health programs.