OBJECTIVE: To retrospectively evaluate the effects of intermittent self-dilatation (ISD) on the natural course of urethral strictures after an internal urethrotomy. MATERIAL AND METHODS: A retrospective case-control analysis of all males who had undergone a first time internal urethrotomy due to a urethral stricture in 1998-2000 at 15 urological departments in Sweden. Out of 217 included patients 162 were treated with internal urethrotomy only and 55 with internal urethrotomy followed by postoperative ISD. Demographic data including stricture localization, stricture aetiology and reoperation dates, as well as postoperative indwelling catheter and antibiotic treatment, were collected from the medical records. Factors concerning the ISD were also gathered: postoperative starting time, dilatation catheter size, dilatation frequency and time for retreatment. All patients' medical records were followed for 3-6 years until 2003. RESULTS: The median time until recurrence (surgical reoperation) was 732 days in the ISD group and 167 days in the non-ISD group (p