Background: There is evidence that physical exercise leads to reduced metabolic derangement in persons with diabetes mellitus 2 (DM2). Objetive: To learn about the effects of physical exercise in controlling DM2. Methods: A pre and post treatment quasi-experimental study was conducted from January to May, 2011. 40 DM2 subjects were assessed. Two subgroups were formed: one with 20 patients (the experimental group) and another one with the remaining 20 patients (the control group). The variables analyzed were: age, sex, body mass index, waist circumference, fasting blood glucose levels, cholesterol, triglycerides and blood pressure (systolic and diastolic). We designed an aerobic exercise program that was applied to the experimental group. We measured the variables for both groups at baseline, at week 6 and 12. Results: Obese people predominated in both groups, with a mean age of 49 years in the experimental group and 48 in the control group. Blood glucose, cholesterol and triglyceride levels all decreased after 6 and 12 weeks in the treatment group compared to baseline values. There was a significant drop of systolic and diastolic blood pressure in the experimental group. A decrease in the average values was found in the remaining variables of the experimental group. Conclusiones: A physical exercise program implemented in diabetics promotes metabolic and existing risk factor control