To document the occurrence of sleep disturbance and bladder dysfunction in enuretic children, 25 children (21 boys, 4 girls, mean age 9.9 years) with monosymptomatic nocturnal enuresis were studied. All children had significant enuretic symptoms (> 4 wet nights per week) which persisted after treatment failure. The investigation protocol included cystometry during the day, simultaneous polysomnographic and cystometric monitoring during the night and recording of diurnal and nocturnal urine output. None of the patients had nocturnal polyuria. According to the presence or absence of sleep disturbance and/or bladder dysfunction, five different patterns could be recognized. These patterns were grouped as having normal and abnormal daytime urodynamics. In conclusion, sleep disturbances and bladder dysfunction are common among enuretic children, especially those who fail to respond to treatment.