Day case surgery for inguinal hernia had been an established practice of the paediatric surgery unit, OAUTHC, Ile-Ife for about two decades. In a retrospective review of the practice by Adejuyigbe et al (1998), a high incidence of postoperative wound infection was noted which they attributed to the poor personal hygiene of the patients. This prospective study, therefore, was performed to evaluate the role of preoperative gentamicin in the prevention of these wound infections after day case surgery for inguinal hernia in children. The study was carried out over a period of eight months from 11th April 2004 to 20th December 2004. During this period, 88 children randomized into control and test groups of equal numbers underwent elective inguinal herniotomy leading to 104 wounds in the ratio of 50:54 in the control and test groups respectively. The children in the test group received prophylactic intravenous gentamicin 30 minutes before a groin crease incision was made, while those in the control group did not. All the patients were subsequently followed up for 32 days for any evidence of a wound infection. All 54 wounds of the children who received prophylactic antibiotics healed primarily and without complication. Five cases of wound infections occurred in the control group, giving an infection rate of 4.8% (5/104 procedures) (P<0.041). This difference was statistically significant meaning that the absence of postoperative wound infection in the test group was probably due to the effect of the gentamicin administered. Staphylococcus aureus was the single pathogen isolated from the infected post-herniotomy wounds and this organism was wholly sensitive to gentamicin. From the findings in this study, administration of preoperative antibiotic has a role in the prevention of wound infection after day case surgery for childhood inguinal hernias. Preoperative antibiotic (gentamicin) is therefore recommended as a prophylactic measure against wound infection after day case surgery for inguinal hernia in children. Similarly, in the event of a severe post-herniotomy wound infection, gentamicin could be used for empirical or definitive treatment of the infection following swab culture and sensitivity result.