AIM: To determine the relationship between pre operative hypoalbuminemia and the development of complications following rectal cancer surgery, as well as postoperative bowel function and hospital stay. METHODS: The medical records of 244 patients undergoing elective oncological resection for rectal adenocarcinoma at Siriraj Hospital during 2003 and 2006 were reviewed. The patients had pre-operative serum albumin assessment. Albumin less than 35 g/L was recognized as hypoalbuminemia. Postoperative outcomes, including mortality, complications, time to first bowel movement, time to first defecation, time to resumption of normal diet and length of hospital stay, were analyzed. RESULTS: The patients were 139 males (57%) and 105 females (43%) with mean age of 62 years. Fifty-six patients (23%) had hypoalbuminemia. Hypoalbuminemic patients had a significantly larger tumor size and lower body mass index compared with non-hypoalbuminemic patients (5.5 vs 4.3 cm; P＜0.001 and 21.9 vs 23.2kg/m2; P=0.02,respectively＝.Thirty day postoperative mortality was 1.2%. Overall complication rate was 25%. Hypoalbuminemic patients had a significantly higher rate of postoperative complications (37.5% vs 21.3%;P=0.014).In univariate analysis, hypoalbuminemia and ASA status were two risk factors for postoperative complications. In multivariate analysis, hypoalbuminemia was the only significant risk factor (odds ratio 2.22,95% CI 1.17-4.23; P＜0.015＝.Hospitalization in hypoalbuminemic patients was significantly longer than that in non-hypoalbuminemic patients (13 vs 10 d, P=0.034), but the parameters of postoperative bowel function were not significantly different between the two groups. CONCLUSION: Pre-operative hypoalbuminemia is an independent risk factor for postoperative complications following rectal cancer surgery.