Introduction: Surgical site infection (SSI) following hydrocelectomy is relatively uncommon, but it is one of the main post-operative problems. We aimed to describe the prevalence of SSI following hydrocelectomy among adult patients, and to assess predisposing risk factors for infection. Methodology: This retrospective cohort study was carried out at a university hospital and included hydrocelectomies performed between January 2007 and December 2014. Diagnosis of SSI was performed according to the Center for Diseases Control (CDC) guidelines. Multivariable logistic regression analysis was used to identify independent risk factors. Results: A total of 196 patients were included in the analysis. Overall, 30 patients were diagnosed with SSI (15.3%) and of these, 63.3% (19/30) were classified as having superficial SSI, while 36.7% (11/30) had deep SSI. The main signs and symptoms of infection were the presence of surgical wound secretion (70%) and inflammatory superficial signs such as hyperemia, edema and pain (60%). Among the 53 patients presenting chronic smoking habits, 26.4% (14⁄53) developed SSI, which was associated with a higher risk for SSI (odds ratio [OR] = 2.84, 95% confidence interval [CI] = 1.27 to 6.35, p < 0.01) in the univariate analysis. In the adjusted multivariable analysis, smoking habits were also statistically associated with SSI after hydrocelectomy (odds ratio [OR] = 2.84, 95% confidence interval [CI] = 1.30 to 6.24, p = 0.01). No pre-, intra-, or post-operative variable analyzed showed an independent association to SSI following hydrocelectomy. Conclusions: Smoking was the only independent modifiable risk factor for SSI in the multivariate analysis.