PURPOSE: Obese patients are generally believed to be at increased risk for surgery compared to those who are not obese. It was the purpose of this study to compare the short-term outcomes of a laparoscopic low anterior resection (LAR) in obese and non-obese patients. METHODS: We retrospectively reviewed 79 patients who had undergone a laparoscopic LAR for rectal cancer between September 2002 and January 2008. The degree of obesity was based on the Body Mass Index (BMI, kg/m2). We divided the 79 patients into two groups: the high BMI (BMI> or =25) and the low BMI (BMI <25) groups. The parameters analyzed included age, gender, American Society of Anesthesiologists classification score, operative time, estimated blood loss, conversion rate, postoperative complications, hospital stay, and oncologic characteristics. Statistics included the t-test and Fisher's exact test. Statistical significance was assessed at the 5% level (P<0.05 being statistically significant). RESULTS: There were no significant differences between the low BMI (n=55) and the high BMI (n=24) groups in age and gender. The high BMI group had significantly more conversion to an open procedure (20.8% vs. 3.6%, P=0.0244). The high BMI group and the low BMI group had no differences in blood loss, complications, hospital stay, and oncologic characteristics, but the high BMI group had a longer operative time (244.2 min vs. 212.0 min, P=0.0035). CONCLUSION: A laparoscopic LAR in obese patients had a higher conversion rate and a longer operative time, but there were no differences in postoperative complications and oncologic characteristics. A further study based on many experiences is needed to clarify the influence of the surgeon's experience on the operative time and the conversion rate, and long-term follow-up is necessary to evaluate the oncologic safety of a laparoscopic LAR in obese patients.