The current study included estimation of Aldose reductase (AR) activity in serum of diabetic  patients. The study included (47) samples of seram from  diabetic patients serum (both types I and II), the patients age ranged from (9-80) years old, and (36) samples of seram from healthy people (control group) aged between (12-80) years old. The results showed significant elevation (P <0.05) in the AR activity in diabetic patients for both types compared with control group. The AR activity was (38.65 ±9.60) IU/ L in the serum of type II diabetes patients and (29.52 ± 5.75) IU/ L in patients with type I diabetes, compared to (11.01 ± 2.19) IU/ L in the serum of healthy people