Zinc was estimated in plasma, leukocytes, erythrocytes and urine of newly-diagnosed cases of diabetes. The patients were all underweight and belonged to socioeconomic groups known to subsist on predominantly cereal-based, calorie-deficient diets. The 24-hour excretion of zinc in urine was found to be significantly high. Evidence is presented to show that this may not be a mere consequence of polyuria. The levels of zinc in plasma, and blood cells were significantly low. It is postulated that hyperzincuria, in the face of a low availability of dietary zinc due to high phytate in cereals, may lead to these low circulating levels of zinc.