Accumulation and dietary transfer of PCBs from contaminated harbor sediments were studied in a laboratory food chain consisting of sediments, polychaetes ( Nereis virens) and a predatory fish ( Leiostomus xanthurus). The study was conducted in two phases to distinguish dietary uptake from PCB accumulation resulting from sediment exposure alone. In phase I fish and polychaetes were separately exposed to field-collected PCB contaminated sediments (5.2 μg/g dry weight as Aroclor 1242 and 1254) in flow-through sea-water systems for 40 days to allow organisms to attain steady state concentrations. In Phase II the dietary fraction of PCB accumulation was determined by selectively feeding exposed and control groups of fish polychaetes having a known PCB body burden. In addition the effect of direct sediment contact on PCB accumulation by L. xanthurus was investigated. Results demonstrate that contaminated sediments can serve as a source of PCBs for uptake and trophic transfer in marine systems. Fish exposed to PCB-contaminated sediments and fed a daily diet of polychaetes from the same sediment accumulated more than twice the PCB whole-body residues than fish exposed to similar conditions but fed uncontaminated polychaetes. The dietary contribution of PCBs accounted for 53% of the total body burden measured in fish fed for 20 days, and this percentage appeared to be increasing. Results also indicate that fish isolated from direct contact with PCB-contaminated sediment do not significantly ( P ≤ 0.05) accumulate PCB residues when compared with fish allowed contact with sediment.