OBJECTIVES: The GALATA study was the first observational study on DPP-4 inhibitors in Turkey and aimed to evaluate the efficacy, safety and tolerability of vildagliptin and metformin combination (VMc) in patients with type 2 diabetes mellitus (T2DM). METHODS: 648 of the 682 screened T2DM outpatients (age >18 years) on VMc for at least 4 weeks prior to enrollment were included in this 24-week, multicenter, observational study. RESULTS: Of the 648 patients, 382 (59.0%) were female. The mean (standard deviation-SD-) age was 55.2 (10.2) years, the mean (SD) T2DM duration was 4.8 (5.2) years and 220 (34.0%) patients had T2DM for more than 5 years. Patients were followed for median (inter-quartile range-IQR-) 184.0 (74.0) days at median (IQR) 4.0 (2.0) visits. Median vildagliptin and metformin doses were 100.0 mg and 2000 mg, respectively. HbA1c decreased from 7.8% to 7.0% (p<0.001). A similar reduction in HbA1c from 7.6% to 7.1% was also seen in elderly patients (>65 years, 18.1% of patients) (p<0.001). The proportion of patients with HbA1c ≤6.5% increased from 13.3% to 42.7% (p<0.001) and those with HbA1c ≤7.0% increased from 26.6% to 65.3% (p<0.001). Mean fasting plasma glucose (FPG) decreased from 153.1 mg/dL to 136.5 mg/dL (p<0.001), whereas mean post-prandial plasma glucose (PPG) decreased from 217.6 mg/dL to 182.1 mg/dL (p<0.001). 80 (12.3%) patients experienced 122 adverse events (AEs) including 3 serious AEs; 2 SAEs were not suspected to be related to VMc. AEs were mostly (94.3%) mild or moderate in severity and no action was taken for 44.3% of them; 76.2% of AEs resolved during follow-up. CONCLUSIONS: The results of the GALATA study suggested that VMc significantly decreased HbA1c, FPG and PPG, achieved glycemic control targets even in elderly patients and demonstrated good overall safety and tolerability in T2DM patients.