Oxygen consumption of toadfish was measured in a closed respiratory chamber using a polarographic oxygen electrode. Cold-acclimated (10°) toadfish were found to consume oxygen at a rate 42% greater than control 21° -acclimated fish, when both groups were measured at 22°. The results indicate that toadfish are capable of partial metabolic compensation in response to low temperatures, comparable to that observed in other poikilothermic vertebrates. The overall metabolic effect appears to correlate well with changes observed in the protein synthetic system of toadfish liver under the same acclimation conditions.