We assessed the incidence, risk factors and causative organism for surgical site infection (SSI). We reviewed the clinical charts of the consecutive 100 patients who underwent radical cystectomy from December 2003 to April 2008. All patients received intravenous prophylactic antimicrobial agent, 1 gram of cefotium hydrochloride before surgery followed by the same agent twice a day through postoperative day 3. Skin closures were carried out by interrupted sutures employing a 3-0 nylon for the first 50 patients (interrupted group), and by buried suture employing 3-0 or 4-0 braided polyglactin for the last 50 patients (buried group). SSI occurred in 13 cases (26%) with interrupted group including 8 patients with ureterocutaneoustomy and 5 patients with orthotopic ileal neobladder reconstruction. On the other hand, SSI was found in 1 patient (2%) in the buried group for whom ileal neobladder reconstruction was carried out (P= 0.021). Superficial inflectional SSI was found in 6 patients (5 patients in the interrupted group, patient in the buried group) and deep incisional SSI occurred in 5 patients in the interrupted group only. The most frequently isolated organism was Enterococcus faecalis. Univariate analysis revealed that body mass index (BMI) and the skin closure methods were significant risk factors for SSI (P<0.001, P=0.021, respectively). These 2 risk factors for SSI were also significant in multivariate analysis (P=0.003, P=0.037, respectively). These results suggested that BMI and the skin closure methods are independent risk factors in radical cystectomy. Furthermore, it may be possible to reduce the incidence of SSI by performing the buried suture for the skin closure.