Background : Surgical site infection (SSI) is a hospital acquired infection that poses great clinical, psychological and financial demand on the patient and healthcare givers. In the study centre, surgical site infection has been a common nosocomial infection and efforts are being directed towards reducing this burden. Aims : To determine the prevalence, bacteriology and antibiotic sensitivity of the causative organisms isolated from the incisional surgical site infection following laparotomies in adult patients. Methodology: This is a prospective cross-sectional study in patients who had elective and emergency laparotomies and their wounds assessed for presence of infection using standardized criteria as stipulated by the Centres for Disease Control and Prevention (CDC). Other outcome measures were the bacteriology and antibiotic sensitivity pattern of infected wounds. Patients’ demographic data and wound outcomes were entered into a proforma designed for the study. Patients with associated co-morbidities (Diabetes mellitus, Retroviral disease et cetera) were excluded. The wounds were inspected on post-operative days 3, 5 and 7 and swabs obtained for microscopy, culture and sensitivity tests in infected cases. Results: There were 291 patients who had laparotomy during the study period, 223 met the inclusion criteria; consisting of 157 (70.4%) males and 66 (29.6%) females (M: F = 2.4: 1). Their ages ranged between 18 and 80 years with a mean age of 33.89 ± 12.57 years. Incisional SSI was clinically diagnosed in 85 patients giving a prevalence rate of 38.1%; 77 (91%) had positive culture results. Sixty three (74.1%) of SSI were superficial SSI while 22 (25.9%) were deep. Single bacterial isolate was seen in 56 (65.9%) patients and the organisms comprised Klebsiella spp (34%), Staphylococcus aureus (30.4%), Proteus spp (19.6%), Providencia (12.5%) and Escherichia coli (3.6%), while mixed infection was seen in 21(24.7%) patients. Isolated organisms demonstrated good sensitivity to the cephalosporins (> 85%), quinolones (>75%) and gentamicin (100%). The duration of hospital stay for these patients ranged between five to ninety days (Mean = 16.69 ± 8.50 days). Conclusion: A high prevalence rate (38.1%) of SSI was observed in this study. Gram negative organisms were the predominant aetiological agents with an attending sensitivity pattern in favour of cephalosporins, quinolones and aminoglycoside. Antibiotics regimen for patients undergoing laparotomies either for prophylaxis or therapeutic purposes should be based on the antibiogram from this study; most especially the cheaper and readily available drugs.