Accumulation of cadmium in gill, liver, muscle and kidney tissues of Cyprinus carpio and Oreochromis niloticus were investigated in fish exposed to 0.5 ppm cadmium over 1, 15 and 30 days under controlled laboratory conditions. Tissue accumulation of the metal was measured using Atomic Absorption Spectrophotometric techniques. Cadmium accumulation in gill, liver, kidney and muscle, tissues of C. carpio and O. niloticus exposed to metal for 1, 15 and 30 days increased significantly compared with the control group (p < 0.05), except muscle tissue of O. niloticus. A general increase was observed in Cd accumulation with increasing exposure periods. Highest metal accumulation was observed in kidney followed by liver, gill and muscle tissues in both species. Liver accumulation of Cd was higher in C. carpio than O. niloticus, whereas kidney accumulation of the metal was higher in O. niloticus than C. carpio.