Aims: This study investigated the relationship between the subjective outcome assessment and objective parameters after intravesical onabotulinumtoxinA injection in patients with overactive bladder ( OAB). Methods: A total of 77 consecutive patients with urodynamically confirmed detrusor overactivity were treated with intravesical 100U of onabotulinumtoxinA in 20 divided injections ( 5U in 0.5 ml normal saline each) at different sites sparing the trigone. The primary end-point was the change in the Global Response Assessment ( GRA) 3 months after treatment. All patients were monitored monthly after treatment for up to 6 months. Patients were divided into successful and failed treatment groups according to change in their GRA ( >= 2 and= 2 had significant improvements in OABSS at 3 months, and USS, OABSS, urgency urinary incontinence ( UUI), and urgency episodes at 6 months compared with patients with GRA <= 1. No significant difference in MBC, PVR, or VE was noted between groups at 3 or 6 months. Conclusions: Subjectively successful treatment outcomes of intravesical onabotulinumtoxinA injection for OAB patients were associated with improvement in OAB symptoms but not increased bladder capacity. (C) 2015 Wiley Periodicals, Inc.