OBJECTIVES: To evaluate of practice and conduct economic analysis of antibiotic prophylaxis (ABP) in intra-abdominal surgery in Smolensk Regional Hospital (SRH) and to assess the impact of educational (lectures, information bulletin) and administrative (practical recommendations) activity in SRH on ABP practice. METHODS: Analysis was based on patient data gathered retrospectively between 01/01/93-01/07/93 and 01/01/98-01/07/98. Three hundred and twenty seven patients who underwent open cholecystectomy (OCE), appendectomy (AE) and hernia repair (HR) were included in analysis. ABP frequency and quality (selection of antimicrobials, dosage regimens, route of administration, post-operative duration) were assessed. For economic evaluation ABP Threshold Cost/Wound Infection Treatment Cost (ABP-TC/WITC) ratio was estimated. ABP-TC was calculated by multiplication Numbers Needed to Treat and ABP cost. RESULTS: In 1993 none of the patients received ABP, in 1998 the following ABP frequency was registered: OCE – 78% (77/99), HR - 46% (18/39), AE – 0%. In case of OCE, I-II and III generation cephalosporins were administrated in 57% and 47% cases, respectively. AB dosages, routes of administrations were appropriate in all cases. TC-ABP/WITC ratio for OCE was 520/5355=1/10.3 (RUB, 1999). In 1993 antibacterial administration without evidence of postoperative infection was registered for OCE in 82%, AE-68%, HR-33% cases; in1998 for OCE in 31%, AE-68%, HR-34% cases. CONCLUSION: (1) ABP in OCE is cost-effective compared to no-ABP strategy and leads to 10 times reduction of hospital costs; (2) Educational and administrative activities have a positive impact on ABP practice; (3) Monitoring of ABP practice and feedback to surgeons should be implemented in hospitals for the optimization of ABP.