The effect of hydrocortisone (HC), the steroid of lowest potency, and physiotherapy (PT) on non-retractile physiologic phimosis (PP) and the reduction of subsequent recurrent UTI was evaluated in male infants with UTI. Seventy-eight male infants with febrile UTI and nonretractile PP were prospectively randomized into HC (Plancol, n=39) and control (Vaseline, n=39) groups. Topical application of HC as a thin film around the preputial margin twice a day for four weeks with PT was instructed. The response rate in the HC group was 89.7% (35/39), which was significantly higher than the rate (20.5%; 8/39) in the control group (P<0.05). In the HC group, the response rate was much higher (96.1%) in the subgroup with PT than in the group without PT. Most of the response (88.5%) was observed within two weeks. During the following year, the recurrent rate of UTI was 7.1% (2/28) in the infants with retractile prepuces, which was significantly less than than the rate (29.6%; 8/27) in infants with nonretractile prepuces (P<0.05). In conclusion, topical HC and PT for 2-4 weeks proved to be a simple, safe and effective treatment for nonretractile PP in infants with UTI, and this procedure was beneficial in reducing recurrent UTI.