The effects of urethral dilatation have been investigated in girls with recurrent urinary infection. About 65 per cent of girls showed some improvement when this procedure was combined with long-term antibiotic therapy, provided that there was no serious vesico-ureteric reflux. However, the results were unpredictable, and in a controlled prospective trial the preliminary results of dilatation did not differ significantly from those obtained with cystoscopy alone. Nevertheless, improvement after dilatation did seem to be associated with a high urethral pressure profile, high bladder pressure, small bladder capacity and marked detrusor irritability; it is suggested that this “dysfunctional bladder syndrome” may be the cause of recurrent infections in these cases, and that improvement may be anticipated after urethral dilatation, which should be combined with anti-cholinergic drug therapy if day wetting is a co-existing problem.