The purpose of this study was to evaluate the efficacy of chromium supplementation as a treatment for gestational diabetes. Of 30 gestational diabetic women (20–24 gestational wk) recruited for study, 20 were randomized into two groups: 10 received 4 μg/d/kg/body weight of chromium picolinate (4 μg CrPic), and 10 received placebo. Ten additional women, matched for glucose intolerance and body mass index to the placebo group, received 8 μg/d/kg/body weight of CrPic (8 μg Cr). All baseline blood determinations and the 100 g glucose load were repeated after 8 weeks of supplementation in all three groups. At baseline, the three groups did not differ for insulin, C-peptide, or glucose levels at the fasting and 1 hr time point after the 100 g oral glucose challenge test. Three women in the 4 μg CrPic group, one woman in the 8 μg CrPic group, and four women in the placebo group failed diet and required insulin.