Fifty-two patients with objective evidence of pressure equalization incontinence and detrusor instability were evaluated retrospectively to compare nonsurgical modes of therapy with retropubic surgery. Based on the patient's desire for surgery and her overall medical condition, 27 women were treated primarily with retropubic urethropexy (modified Burch procedure) and 25 with various combinations of oxybutynin, imipramine, and estrogen. Thirty-two percent of the patients treated medically were cured and 28% were markedly improved, whereas 59% of patients treated surgically were cured and 22% improved. There was no statistically significant difference in the results between medical and surgical therapy. All failures in the surgically treated group were due to persistent detrusor instability after surgery. We identified no preoperative urodynamic criteria that consistently and accurately predicted surgical outcome in patients with combined stress and urge incontinence. Patients with combined stress incontinence and detrusor instability should initially be managed medically, as this will reduce the incidence of surgical intervention.