Intermittent catheterization is used commonly to treat bladder dysfunction. We treated 10 patients who were experiencing difficulty with intermittent catheterization, 9 of whom had a false urethral passage. Of these patients, 6 had previously undergone a bladder neck or urethral operation. Endoscopy was helpful to diagnose the condition. Treatment consisted of stenting in 3 patients, transurethral incision and stenting in 3, and fulguration and stenting in 4. An indwelling catheter was left in place for 2 to 3 weeks, after which intermittent catheterization was resumed with a softer catheter. Two patients again experienced severe difficulty with catheterization and they underwent a continent urinary diversion. When intermittent catheterization becomes difficult or impossible, the presence of a urethral false passage should be suspected as a possible cause.