This study was conducted to investigate chromium metabolism and the effect of chromium supplementation in patients with Turner's syndrome, a condition noted for its high incidence of diabetes. Oral glucose tolerance tests were performed in 14 patients 8 to 19 yr of age. Eight of the 14 subjects were given 30 g of brewer's yeast containing 50 micrograms of chromium every day for 8 wk and glucose tolerance tests repeated. Urine samples were collected before and after each glucose load. Serum lipids were also investigated. Before supplementation, urinary chromium/creatinine ratio was high, and the urinary chromium response to oral glucose tolerance test was absent. Cholesterol and/or triglyceride levels were high in three of the patients. After supplementation, a decrease in urinary Cr/Cre ratio, and an improvement in glucose area index total were noted. A decrease in cholesterol and/or triglyceride levels occurred in the three patients with high initial levels as well as an increase in high-density lipoprotein cholesterol. These findings indicate a state of chromium deficiency and support the hypothesis that chromium deficiency may have a role in the pathogenesis of the abnormal glucose tolerance tests encountered in Turner patients.