As there are raised intra-cellular sodium concentrations in both depression and essential hypertension we have studied serum elements in small groups of male hypertensives, male controls, female hypertensives and female depressives. There were no changes in serum vanadium or lithium concentrations. The most significant results were for bromine and tin which were reduced in both the hypertensive groups. Less significant were increased cobalt and increased molybdenum in both hypertensive groups.