We aim in our systematic review and meta-analysis to summarize and evaluate the efficacy of laparoscopic sleeve gastrectomy (LSG) and laparoscopic Roux-en-Y gastric bypass (RYGB) as two types of bariatric surgery in reducing the body mass index (BMI) and controlling the glycemic state in obese, diabetic patients. Our systematic review and meta-analysis (MA) were carried out according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for randomized studies. We searched PubMed, Web of Science, Scopus, and Cochrane library for included studies. We chose randomized controlled trials (RCTs) assessing the efficacy of LSG and RYGB in controlling the glycemic state in obese patients; then we used Review Manager software to pool the outcomes of our MA. Three RCTs were included in our meta-analysis. The outcomes evaluated were BMI and HbA1C. As for the BMI, the results were significant and favor LSG and RYGB post-operatively as follows: mean difference (MD) 0.30; confidence interval (CI) 0.07–0.54; P value 0.010. Also, the results were significant regarding HbA1C as follows: MD 0.30; CI 0.07–0.54; P value 0.010. Bariatric surgeries, especially LSG and RYGB, improve the glycemic state and reduce BMI in obese diabetic patients.