OBJECTIVE: To study the long-term outcome of patients undergoing enterocystoplasty. PATIENTS AND METHODS: The study comprised 48 patients (17 men and 31 women; mean age 46 years) who underwent enterocystoplasty for idiopathic detrusor instability (DI, 35 patients) or neurogenic bladder dysfunction (13 patients). Symptoms were scored from 0 to 14 and the overall outcome and generic quality of life were assessed using a Visick grading system (groups A to E) and the Nottingham Health Profile (NHP). These assessments were carried out before, 3 months after operation and at the final follow-up (38 +/- 18 months, range 13-78). Urodynamic studies were performed before and after operation. RESULTS: No patient died after operation and there was minimal early morbidity. Late complications (> 30 days) included incisional hernia (3), anastomotic perforation (1), calculus formation (1) and urethral stricture (1). Clean intermittent self-catheterization (CISC) was performed by 36 (75%) patients. Early symptomatic outcome was good in 40 (83%) patients, moderate in seven (15%) and unsatisfactory in one (2%) patient. The mean symptom scores before and 3 months after surgery were 10 (range 2-14) and 3 (range 2-14), respectively (P < 0.001). There was a significant increase in total bladder capacity (307 +/- 140 to 588 +/- 217 mL; P < 0.001) and bladder compliance (37 +/- 50 to 169 +/- 162 mL/cm H2O; P < 0.001). DI persisted in 15 (31%) patients. NHP scores revealed significant improvements in all domains. Final assessment showed a less satisfactory situation, with recurrent urinary tract infection (UTI) in 17 (37%) patients, a need for long-term antibiotic therapy in seven (15%) and a change in bowel habit in 15 (33%) (13 DI, two with neurogenic bladder dysfunction). CISC was performed by 39 (85%) patients. The long-term outcome was good or moderate in 12 patients (92%) with neurogenic bladder dysfunction and good or moderate in only 19 patients (58%) with DI. CONCLUSION: Clam enterocystoplasty remains an effective management option in some patients with DI, but most patients with neurogenic bladder dysfunction do well. The procedure is, however, associated with long-term complications such as disturbance of bowel habit and recurrent UTIs, which impair the outcome in the long-term in patients with DI despite general improvements in irritative bladder symptoms.