Mg and PO<sub>4</sub> concentrations were significantly higher in unmixed parotid saliva from chronic renal failure (CRF) patients than in controls. No significant differences were noted in the flow, pH or concentrations of Na, K, Cl or Ca; however, the Na/K ratio was significantly lower in CRF patients. No correlation between plasma PTH levels and the concentrations of Ca, Mg, or PO<sub>4</sub> in saliva was found. Taken with previous results from elevated divalent ion concentrations in sweat from CRF patients, these findings suggest that the excretion of divalent electrolyte glands may represent a generalized abnormality in exocrine glands in CRF. We hypothesize that the active processes involved in regulating the concentrations of these ions in exocrine secretions are altered so that larger amounts of these elements are excreted in CRF patients.