A spatially comprehensive evaluation of polychlorinated biphenyl (PCB) inventories in white perch, channel catfish, small prey fish, amphipods and sediment within four zones of the Delaware River Estuary was completed during two seasons (fall 2001 and spring 2002). Highest sediment PCB concentrations occurred adjacent to urbanized and industrialized stretches of the estuary. Whole organism MICB body burdens (on a wet weight basis) reflected the spatial distributions in sediment PCB concentrations. However, there was considerable variation in PCB concentrations among individual catfish and perch fillets within zones that were not significantly reduced by lipid normalization. This variation suggests that within a zone man), factors (e.g., dietary shifts, small-scale heterogeneity in sediment contamination, and non-equilibrium conditions in contaminant partitioning) drive PCB bioaccumulation. With increasing down-estuary distances, all biota except for perch had enhanced concentrations of more chlorinated congeners, especially nona- and deca-chlorinated biphenyls. Specific congeners such as PCB 206 and 209 may act as indicators of unique local sources of contamination within the lower portions of the Delaware River Estuary.