Phosphate depletion is associates with abnormalities of the central nervous system (CNS) and of the cardiovascular system. Since alterations of catecholamines content in the CNS may contribute to these abnormalities, we studied the effect of phosphate depletion on catecholamine content of various areas of CNS in rat. Phosphate-depleted rats showed significant reduction in both dopamine and nonrepinephrine concentrations of medulla oblongata, hypothalamus, striatum and midbrain. However, epinephrine levels were significantly reduced only in the hypothalamus and not in any other regions studied. Dopamine content of cerebral cortex, cerebellum and norepinephrine content of cerebellum were not affected. These changes could contribute to the CNS abnormalities observed in phosphate depletion, but they may also be a consequence of altered energy metabolism coupled with hypotensive effect seen in phosphate-depleted animals.