The prophylactic effect of a intraoperative intraperitoneal and subcutaneous application of cefazolin versus a single shot i.v. prophylaxis was investigated. Additionally, we registered the concentration of cefazolin in the serum and the peritoneal fluid in 22 patients. We randomized 200 patients of whom 189 were included in the study. Ninety-two patients received the prophylaxis i.v. (group 1) and 97 topically (group 2). In 4 (2.1%) wound infections occurred [3(3.3%) group 1 and 1 (1.0%) in group 2]. The difference was not significant. The concentration of cefazolin in the serum was significantly higher at 1 h and 2 h postoperatively in group 2. We conclude that a topical application of antibiotics is possible to prevent surgical wound infection.