Copper (Cu) accumulated in the livers of sheep receiving high levels of dietary Cu but low levels of molybdenum (Mo) and sulphur (S). However. the liver Cu accumulation was much lower than levels found in similar trials in the literature. It is suggested that the minerals present in broiler litter and antagonistic to Cu absorption could have been responsible for this lower Cu accumulation. No additional S was required to obtain the depressing effect of Mo on liver Cu accumulation because of the high S content of broiler litter. The feeding of additional Mo produced a dramatic increase in kidney Cu levels as well as a rise in blood serum Cu and spleen Cu levels. No indication of Mo toxicity was observed