Objective: Prostate biopsy for the diagnosis of prostate cancer by transrectal ultrasonography (TRUS) is a common procedure used in daily urology practice with a low complication rate and easy applicability. In this study, the precipitating factors and prophylaxis for sepsis, the worst complication of the procedure, were assessed. Patients and Methods: 2,023 patients with suspected prostate cancer who underwent biopsy by TRUS in one center were assessed retrospectively. The relationship between sepsis and age, serum total prostate-specific antigen (PSA) level, PSA density, prostate volume, number of biopsies, number of repeated biopsies, accompanying diagnosis of prostatitis, presence of urethral catheter, and presence of diabetes mellitus was assessed. Data were analyzed using the t test and logistic regression analysis. Results: Of the 2,023 patients, 62 (3.06%) developed sepsis within 5 days after biopsy. There was no significant relationship between the biopsy and the above parameters using the logistic regression analysis. Using the t test, it was found that the number of biopsy cores (p < 0.001), presence of urethral catheter (p < 0.0001), and presence of diabetes mellitus (p < 0.0001) were predictive factors for sepsis. Conclusion: Sepsis is a rare but life-threatening complication after prostate biopsy by TRUS. Although preoperative prophylactic oral antibiotics and enema before biopsy have proven to be effective in decreasing urinary tract infection rates, patients with urethral catheter, diabetes mellitus or those to undergo biopsy from more sites than ten cores should be closely monitored after biopsy.