This study investigated the effect and safety of solifenacin succinate liquid suspension compared to a non-active drug (placebo) over a 12-week period. The 2 weeks prior to the double blind period was a single-blind placebo run-in period in combination with behavioral urotherapy (Non-interventional diary assisted urotherapy consisting of overactive bladder (OAB) information, awareness, instruction, life-style advice and documentation of voiding habits and symptoms for OAB), followed by a 12 week daily treatment period. The study also investigated how well solifenacin succinate suspension is taken-up by the body and how long it stays in the body during this time.