A multiresidue method based on normal-phase LC for the sample clean up of whale tissues extracts prior to GC-MS determination of residues of polychlorinated biphenyls, organochlorine pesticides and derivatives and lipophylic organophosphorus pesticides has been developed. Pesticides were extracted from blubber by fusing and dissolving the fat in n-hexane and from liver and kidney by reflux in n-hexane. Hexanic extracts were directly injected on the silicagel column of the automated LC clean up system, using n-hexane as mobile phase. Diode array detection allowed the on-line monitoring of lipids elution from the LC system. Purified extracts were analysed by GC using mass selective detection. The developed procedure was applied to different tissues from a whale specimen appeared in the Valencian coast, finding high concentrations of OCs (up to 7.3 micrograms g-1 pp'-DDE, and 7.2 micrograms g-1 PCBs). The method was validated by means of recovery tests for all the compounds detected in the whale and also for some other OCs and OPs studied in this paper. The method improves other current methods for the analysis of persistent organochlorines in marine mammals with regard to time of analysis, solvent expend and automation; solvent exchanges are not necessary before GC analysis, and it allows the simultaneous determination of organophosphorus pesticides.