BackgroundDiabetes is closely linked with coronary artery disease, either by means of direct effects of hyperglycemia, or indirectly by its frequent association with dyslipidemia. Any treatment for diabetes that has beyond the capacity of reduce glycated hemoglobin, the propensity to improve lipid profile and reduce weight will bring many benefits to patients.MethodWe compare the effects of vildagliptin with the gliclazide on lipid profile before and after a standardized meal test, on glycemic control and oxidative stress in diabetic patients using metformin without adequate glycemic control. This is a prospective study of 16 weeks with diabetic patients using metformin without adequate glycemic control. Patients were randomized to receive gliclazide 30–120 mg/day or vildagliptin 100 mg/day.Results36 patients were randomized, with no loss of follow up. Regarding the lipid profile the difference observed at the end of the study was a higher HDL level in the vildagliptin group compared with gliclazide fasting (62.3 vs. 51.3 mg/dL, p = 0.021) and postprandial (62.9 vs. 51.1 mg/dL, p = 0.015). We also observed a variation of negative weight (decrease the end compared to the beginning) of the vildagliptin and a positive (increase) in the gliclazide (−0.3 vs. +1.4 Kg, p = 0.048). The decrease in A1c was lower in the vildagliptin group compared to gliclazide (−1.7 vs.−2.3 %, P = 0.031), however there was no difference in the number of patients reaching target glycated hemoglobin <7 % (50 vs. 61.1 %, p = 0.738). Only the group of vildagliptin presented at the end of the study compared to the beginning, decreased insulin values (599.6 vs.705, 59 pg/ml, p = 0.021), glucagon (46.6 vs.65, 2 pg/ml, p = 0.004) and the marker of oxidative stress TBARS (8.0 vs. 9.0 nmol MDA/ml, p = 0.035).ConclusionVildagliptin showed some advantages in addition to metformin in relation to addition of gliclazide. Patients treated with vildagliptin had a higher HDL at the end of the study, less variance in weight, reduced insulin and glucagon as well as reduction of oxidative stress.