A five-month prospective survey of surgical-site infections (SSI) was conducted in the department of general surgery at Kilimanjaro Christian Medical Center, Tanzania. SSI were classified according to Centers for Disease Control and Prevention (CDC) criteria and identified by bedside surveillance and post-discharge follow-up. This study showed that 77 (19.4%) of the patients developed SSI. Twenty-eight (36.4%) of these infections were apparent only after discharge from hospital. Eighty-seven percent of those who developed SSI had received antibiotic prophylaxis. Significant risk factors for developing SSI during hospital stay were: operations classified as contaminated or dirty, operations lasting for more than 50 min and the length of preoperative stay. The only significant risk factor for those who developed SSI after discharge was having undergone a clean-contaminated operation. Staphylococcus aureus was the most frequently isolated micro-organism followed by Escherichia coli and Klebsiella spp., most of which were multi-resistant. An exception was S. aureus where 54.5% of the isolates were fully susceptible. The incidence of SSI and the prevalence of antibiotic resistance in this teaching and tertiary care hospital are high. The risk factors were similar to those reported from countries with more resources. The findings suggest that infection prevention measures, particularly antibiotic prophylaxis, should be re-evaluated.