Background: Solifenacin, an effective, well-tolerated treatment for adult overactive bladder (OAB) symptoms, has not been evaluated in placebo-controlled paediatric clinical trials. Objectives: To evaluate the efficacy and safety of once-daily oral solifenacin suspension in OAB patients aged 5-< 12 yr (children) and 12-= 3 wk at the optimum dose before end of treatment (EoT). Outcome measurements and statistics: Superiority of solifenacin versus placebo in change frombaseline to EoT for mean volume voided/micturition (MVV, primary endpoint); daytime maximumvolume voided/micturition (DMaxVV); incontinence episodes (mean/24 h); mean number of incontinence-free days or nights/7 d; micturition frequency; and Micturition frequency adjusted for baseline total voided volume (VTB) as an exploratory parameter). Efficacy parameters were analysed using analysis of covariance. Safety parameters (treatment- emergent adverse events, serious adverse events, laboratory variables, vital signs, electrocardiogram, postvoid residual volume) are summarised using descriptive statistics. Results and limitations: In children, solifenacin was superior to placebo in terms of the change from baseline to EoT for MVV (solifenacin-placebo difference 12.1 ml, 95% confidence interval [CI] 0.2-24.0; p = 0.046), DMaxVV (difference in adjusted mean change from baseline for solifenacin-placebo 31.9 ml, 95% CI 4.3-59.5; p = 0.024), VTB-adjusted micturition frequency (p = 0.028). Other endpoints were not significantly different. Solifenacin was well tolerated. For adolescents, it was not possible to draw firm efficacy conclusions because of the low numbers recruited. Conclusions: Once-daily solifenacin oral suspension in children with OAB was superior to placebo for MVV (primary efficacy endpoint) and was well tolerated. Patient summary: In this 12-wk study, a once-daily oral suspension of solifenacin in children aged 5-< 12 yr with overactive bladder was superior to placebo in increasing mean volume voided/micturition, the primary efficacy variable in the study. Solifenacin was well tolerated, with a low incidence of dry mouth and constipation. This study is registered at ClinicalTrials.gov as NCT01565707. (C) 2016 European Association of Urology. Published by Elsevier B.V. All rights reserved.