A method has been developed for the analysis of non-ortho substituted chlorobiphenyls (CBs) in fish. The method consists of a saponification, clean-up over alumina and silica and HPLC fractionation over porous graphitic carbon. GC/NCI-MS is used for the final determination. Concentration of non-ortho CBs have been measured in Aroclor 1254, several fish samples and dolphin blubber.