Although it has been pointed out that the main cardiovascular risk factors in diabetic are dyslipidemias, hypertension, and cigarette smoking, very few studies have analyzed other risk factors, such as sedentarism and maximal aerobic capacity (VO2 max). The purpose of this study was to evaluate VO2 max and blood lipids (total cholesterol = TC, high density lipoproteins cholesterol = HDL; low density lipoproteins cholesterol = LDL; triglycerides = TG), in 19 diabetics subjects, 19 sedentary and 19 long distance runners. The diabetics of 5-10 years of evolution were non obese (body fat < 28%), and in regular metabolic control (Hb A1 < 12%). The athletes had more than five years of uninterrupted training. The diabetics had significantly lower VO2 max, than the other groups. The mean +/- SEM (mL/kg/min) in diabetics was 30.5 +/- 1.6 versus 41.3 +/- 2.3 in the controls and 54.2 +/- 2.5 in the athletes. There were significant group differences in TG (218 +/- 44 in diabetics vs 106 +/- 16 in controls and 94 +/- 10 mg/dL in athletes) and in HDL (27.3 +/- 4.3 in diabetes versus 34.1 +/- 4.3 and 43.9 +/- 6.3 mg/dL). These data suggest that sedentarism and low VO2 max may be important risk factors in diabetics. An aerobic program for them could perhaps change their blood lipids favorably as their VO2 max was significantly correlated with TG (r = -0.45), HDL (r = 0.52) and the TC/HDL ratio (r = -0.57).