Abstract : In the past twenty years, bariatric surgery has witnessed a huge demand by obese patients, especially those who suffer from related diseases. The current study aimed to compare the outcomes of a single anastomosis sleeve ileal bypass (SASI) and laparoscopic sleeve gastrectomy (LSG). In this cohort retrospective study, 80 obese adult patients who underwent bariatric surgery participated, 40 of them for SASI versus 40 others for LGS surgery in a private hospital in Kirkuk governorate, northern Iraq. All participants were followed up after the sixth and twelfth months after the operation. The outcomes were evaluated through of weighing loss, betterment of comorbidities, and complications that were observed after surgery. The results showed that the percentage of excess weight loss at six months after surgery was analogous between both surgeries while bypassing SASI showed a clear elevation of EWL% at twelve months postoperatively when compared with LGS. As for comorbidities, the improvement in type 2 diabetes mellitus and GERD by bypassing SASI was significantly better than that of LGS. As for postoperative complications, it has been proven that there are fewer complications after SASI surgery compared to LGS, but not significant. It was concluded that bypassing the SASI gave better results, especially after twelve months of the operation, and further articles are needful to compare the outcomes of SASI bypass over a longer term.