A laboratory microcosm study was performed to assess the outgassing potential of PCBs from sediment-water systems. PCBs collected in the headspace of the sampler units were adsorbed onto polyurethane foam plugs, which were intermittently sampled over a total period of 56 days. The sediment composition, the level of PCB contamination in the sediment, and incubation temperature were all found to influence the rate of outgassing. Total outgassing losses over the 56 days ranged between 0.04 and 2.5% of the initial sediment PCB burdens.