Minimally invasive treatment of urinary incontinence has become a subject of major interest in recent years. We examined the use of transurethral collagen injection for incontinence treatment. A total of 48 patients were selected for this procedure from April 1993 to February 1997-26 male patients (19 post-RPX incontinence and 7 post-TUR incontinence) and 22 female patients (all after previous incontinence surgery) were treated by injection of collagen into the continence region. The whole group underwent an average of 1.8 sessions, and a mean collagen injection volume of 14.5 ml was delivered per session. Mean follow-up was 9.2 months. Of the female population, 68.2% were cured or greatly improved. In the male population only 47.3% of the post-RPX patients and 6/7 of the post-TUR patients benefited from the procedure. In males, treatment outcome depends on the degree of pretreatment incontinence, because all grade III incontinence patients did worse. Therefore we conclude: transurethral collagen injection is an interesting method in the treatment of urinary incontinence if proper patient selection is assured.