SUMMARY— Three different studies were conducted to evaluate the accuracy and reliability of a widely accepted method for determining organochlorine pesticide residues in animals' tissues. These investigations involved laboratories of both state and federal regulatory agencies. Various adipose tissues, heat-extracted and non-heat-extracted, spiked and unspiked samples were analyzed by these laboratories. Results of these studies demonstrated many inaccuracies and inconsistencies associated with using the current method. The laboratory performing the analysis, as well as the tissue sample used, was shown to significantly (P < .05) affect the results. Further, the heat-extraction phase, as well as the subsequent analytical phase of the method, was observed (P < .05) to present problems of repeatability.