The effect of soil water content on the fate of applied 1 4 C labelled 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (p,p-DDT) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p -DDE) was examined over a 42 day period in laboratory microcosm experiments. Residues released as CO 2 and volatiles during the experiments were measured, as were acetone/hexane extractable and unextractable (bound) residues at the conclusion of the experiments. Release of 1 4 CO 2 was low (<0.7% of added label) under unflooded conditions and virtually zero from flooded soil. Autoclaving soil prior to the experiment essentially eliminated 1 4 CO 2 release. In unflooded, unautoclaved treatments mean binding of p,p -DDT and p,p -DDE ranged between 6.7 and 9.7%. Increased binding of p,p -DDT (24.5%) and p,p -DDE (11.5%) was observed under flooded unautoclaved conditions. Reducedp,p -DDT binding was observed where flooded soil was autoclaved prior to the experiment. Flooding soil containing 1 4 C-p,p -DDT resulted in considerable accumulation of labelled p,p -DDD, demonstrating the capacity within the soil for this transformation, and suggesting that the absence of relatively rapid DDT degradation viap,p -DDD is due to prevailing conditions, rather than the lack of degradative capacity within the microbiota.