The response of the adrenal gland to zinc deficiency was examined in male weanling rats. In comparison with decapsulated adrenals from ad libitum fed controls, glands from zinc deficient rats had greater relative weight (mg/g body wt), DNA concentration, and total lipid and cholesterol concentrations as well as a smaller protein/DNA ratio. Several of these differences (protein/DNA and cholesterol concentration) could be attributed to the inanition accompanying zinc deficiency, as zinc deficient values were similar to those of pair fed controls. Values for total DNA and protein concentration were similar for all groups. Electron micrographs of the zona fasciculata showed a small number of lipid droplets in the adrenals from ad libitum fed controls, an increase in lipid droplets from pair fed controls, and an even more striking increase in lipid droplets from the zinc deficient adrenals. The increased adrenal lipid composition in the zinc deficient group may be secondary to enhanced steroidogenesis or a zinc deficiency-induced defect of lipid metabolism.