AIM:To evaluate the aqueous humor and serum levels of chromium(Cr) in cataract patients with and without 2 type diabetes mellitus·METHODS:Levels of Cr were measured using atomic absorption spectrometry in the serum from 40 patients and aqueous humor aspirates taken during anterior segment surgery from 19 eyes of 19 patients who had diabetic cataracts(diabetic group)and from 21 eyes of 21 patients who had senile cataract only(control group)·RESULTS:The mean aqueous humor Cr concentration in eyes with diabetes cataract was significantly lower than that from eyes with senile cataract(P<0.05).There was also a statistically significant difference between the serum Cr concentrations of the diabetic group and the control group(P<0.05).Serum and aqueous humor chromium content in both groups showed no significant correlation(r=-0.142,P>0.05)·CONCLUSION:The aqueous humor and serum Cr levels are decreased in eyes with diabetic cataract.Cr has an important role in the development process of cataract in patients with diabetes.