The risk to develop an infection after surgery depends on several factors. Those factors may be interdependent or not, depending on the nature of the surgery and the general condition of the patient. The aim of the present study was to identify the factors involved in the occurrence of the Surgical Site Infections (SSI) in the National referral general hospital of N’djamena (Chad). We first realized an interview in the emergency services and in the general surgery of the hospital. The information collected allowed us to draw up survey sheets. An investigation was then conducted on 152 patients who had surgery and were hospitalized during the study period. The frequency of the SSI was 33.6% (51/152). The main risk factors that we identified were the duration of hospitalization, the category of the hospitalization room, the urgent aspect of the surgical intervention, the patient’s nutritional status and the associated diseases with diabetes, which was present in 52.38% (11/21) of cases of associated pathologies. Analysis of the antibiotic prophylaxis administered to patients showed that ciprofloxacin was more effective in SSI prevention. Indeed, this antibiotic showed the fewest cases of infection with only 1.9% of patients having developed SSI. Our results show a very high frequency of SSI at the National referral general hospital of N’djamena. Poor hospital practices and factors associated to patients seem to be the most factors implicated in the SSI.