The constantly growing incidence of obesity represents a risk of health complications for individuals, and is a growing economic burden for health care systems and society. The aim of this study was to evaluate the efficacy of bariatric surgery, specifically laparoscopic greater curve plication, laparoscopic sleeve gastrectomy, and Roux-en-Y gastric bypass, in patients with type 2 diabetes mellitus. The effect of bariatric surgery on the changes in blood pressure before, and 12 months after, surgery and in pharmacotherapy in the 12 months after surgery was analyzed. For achieving this purpose, 74 patients from the Obesity and Surgery Department of Vitkovice Hospital in Ostrava in the Czech Republic, were monitored. They were operated in 2011 and 2012. The Bonferroni method was used to test hypotheses about the impact of surgery on blood pressure and pharmacotherapy. One year after the surgery, systolic and diastolic blood pressure values decreased, both with no statistically significant difference between surgery types. Improvement was observed in 68% of cases, with 25% of patients discontinuing pharmacotherapy entirely.