Purpose: Fever occurring post transurethral resection of prostate (TURP) due to urinary tract infection (UTI) is a well-known complication. A better knowledge of pre-operative risk factors will aid the prevention and treatment of this complication. Herein we aimed to describe the risk factors for postoperative fever in a cohort of patients undergoing TURP in a single institute. Methods: A total of 177 patients underwent transurethral resection of prostate (TURP) between January 2016 and August 2017 in our Institute. Postoperative fever was defined as ≥ 38 ℃ up to a week after surgery. Other reasons for post-operative fever were excluded. We collected data for indwelling catheter, antibiotic prophylactic treatment, positive preoperative urine culture, diabetes mellitus (DM), combined cystolithotripsy and prostate size. Results: All patients received antibiotic prophylaxis prior to the TURP procedure. Patients with negative urine culture were treated with IV Amikacin + Ampicillin (n = 83), whereas patients with positive bacterial cultures were treated as per antibiotic sensitivity profile (n = 93). One patient developed fever in the negative culture group, compared to 8 in the positive urine culture group (P = 0.0375). No patient developed septic shock. Smaller prostate size (RR = 1.06, CI-95%, 1.01-1.12, P = 0.016), positive urine culture (RR = 3.85, CI-95%, 1.33-100, P = 0.033) and older age (RR = 1.1, CI-95%, 1.01-1.21, P = 0.031) were all predictors of postoperative fever. In contrast, TURP combined with cystolithotripsy (P = 0.99), indwelling urethral catheter (P = 0.155), and patients with DM (P = 0.256) were not predictors of postoperative fever. Conclusions: Positive urinary bacterial culture prior to TURP is a frequent event. Although positive urinary culture increased the risk of post TURP fever, none of these events caused significant morbidity. Surprisingly, a smaller prostate size increased the risk of postoperative fever. This fact suggests that the degree of infection is attributed to the level of obstruction and not to the volume of the prostate.