Common analytical methods for detecting and quantifying polychlorinated biphenyls (PCBs) in environmental samples rely on matching a pattern of peaks to a series of Aroclor standards. Due to differences in degradation, partitioning, and metabolism, the PCB pattern in environmental samples can be very different from the Aroclor standards, making identification and quantification of PCBs difficult. To identify an appropriate approach for PCB analyses, the U.S. Environmental Protection Agency Region 9, Biological Technical Assistance Group (BTAG), has considered PCB environmental fate and ecotoxicity, reviewed methods and laboratory capabilities for PCB analysis, and evaluated site-specific data from California and elsewhere. Results of this review indicate analytical methods for routine measurement of specific PCB congeners are currently available, and are cost-effective in comparison with Aroclor- based methods. Accordingly, BTAG has developed a core list of congeners and a phased approach for PCB congener-specific analysis in ecological risk assessments.