The introduction of simple, measures in addition to usual aseptic and antiseptic measures at the University of Ilorin Teaching Hospital theatre in Ilorin, Nigeria, led to a significant decrease in perioperative infection rate in a pilot study. These measures were applied to 440 operative procedures in a unit over a 7-year period in an old as well as new theatre. Sterility tests on sterilizing packs, nasal and throat swabs and bacteria-carrying particle samplings were done to document and limit the sources of wound contamination. Mortality and infection rates were significantly higher among patients undergoing thoracic than extrathoracic surgical operation (P less than 0.05; p less than 0.005) including post-tube thoracostomy empyema. Clean and clean-contaminated cases survived operations significantly more frequently and were significantly less infected than the contaminated and dirty cases (less than 0.001; p less than 0.005). Although there was significantly higher mortality (p less than 0.05) in patients older than 31 years, there was no significantly higher infection rate. Neither the mortality rate nor infection rate was significantly affected by seasonal and patients' sex. Overall infection rate was 7.5% (32 out of 428 fully evaluated patients) while wound and non-wound infection rate in this study is an improvement over those previously reported in this country.