INTRODUCTION: Bariatric surgery is considered an effective treatment for weight loss and for improving the metabolic profile of patients with obesity. Obesity-related comorbidities such as hyperlipidaemia and type 2 diabetes mellitus (DM) are significant cardiovascular risk factors. Additionally, prospective clinical trials have shown that statins increase the risk of development of DM, and many patients with obesity are on statins. We retrospectively examined the effect of bariatric surgery on lipid profile, DM control and weight loss at the five-year follow-up. METHODS: In total, 104 patients undergoing bariatric surgery from 2008 to 2012 were retrospectively studied. 36 patients were on preoperative statins. Their lipid profile, DM control and weight loss were examined at the one-year and five-year follow-ups. RESULTS: Both high-density lipoprotein and triglyceride levels showed significant improvement at the one-year and five-year follow-ups (p = 0.01). Total cholesterol showed significant improvement at the one-year follow-up (-0.30 mmol/dL, p = 0.0338); however, better control was not sustained at the five-year follow-up (-0.15 mmol/dL, p = 0.133). Low-density lipoprotein did not show any considerable improvement at the one- and five-year follow-ups (-0.27 mmol/dL, p = 0.150 and -0.24 mmol/dL, p = 0.138, respectively). A statistically significant improvement in DM control was observed in these patients and in those on preoperative statins. Weight loss was sustained at one and five years. CONCLUSION Bariatric surgery does not confer a uniform improvement in lipid profile in the long term. It does, however, induce efficient weight loss and improvement in diabetic profile, even in patients on preoperative statins.