Acromegaly is known to be associated with both increased cardiovascular mortality and carbohydrate intolerance. The aim of our study is to compare intima-media thickness, a marker of atherosclerosis in active acromegalic patients with and without diabetes. 32 active acromegalic patients (M/ F: 15/17, 16 diabetic and 16 nondiabetic) were assessed for fasting blood glucose (FBG), insulin, growth hormone, insulin-like growth factor 1 and carotid intima-media thickness (IMT). Diabetic patients were significantly older than nondiabetic patients (51.94±10.17 vs 41.38±13.43 years, P=0.018). Diabetes was diagnosed after the onset of acromegaly in all subjects in diabetic group and well-controlled with diet and/ or oral antidiabetic drugs. IMT was significantly higher in acromegalic patients with diabetes compared to nondiabetic group (0.72±0.16 vs 0.60±0.08 mm; P=0.018). GH and IGF-1 levels were similar in both groups. In whole group, age and FBG was correlated significantly with IMT (r=0.438; P=0.015 and r=0.444; P=0.014, respectively), GH, IGF-1 and fasting insulin were not. In conclusion, advanced age and hyperglycemia seems to have a significant impact on the progression of atherosclerosis in the course of acromegaly.