Objective: To develop and evaluate a risk-based antibiotic prophylaxis protocol for patients undergoing transrectal prostate biopsy. Methods: We created a risk-based protocol for antibiotic prophylaxis before transrectal prostate biopsy. Patients were screened for infection risk-factors with a self-administered questionnaire. The protocol was implemented from January 1, 2020 to March 31, 2020. We compared patient risk-factors, antibiotic regimens, and 30-day infection rates for patients undergoing transrectal prostate biopsies during the intervention and for a 3-month period before the intervention. Results: There were 116 prostate biopsies in the preintervention group and 104 in the intervention group. Although there was no significant difference in the number of high-risk patients between the 2 groups (48% vs 55%; P = .33), the percentage of patients treated with augmented prophylaxis decreased from 74% to 45% (P = 0.03). The duration of antibiotic administration and the median number of doses prescribed also decreased significantly. Despite significant decreases in antibiotic use, there were no differences in infection rates (5% vs 5%; P = .90) or sepsis rates (1% vs 2%; P = .60). Conclusion: We developed a risk-based protocol for prophylactic antibiotics before prostate biopsy. The protocol was associated with less antibiotic use but did not lead to an increase in infectious complications.