A Long-term Study of YM178 in Symptomatic Overactive Bladder Patients

Inclusion Criteria: * Subject has symptoms of overactive bladder for \>= 24 wks * Subject experiences frequency of micturition at average \>= 8 times per 24 hrs confirmed by the 3-day patient diary Exclusion Criteria: * Subject is breastfeeding, pregnant, or intends to become pregnant during the study * Subject obviously has stress incontinence * Subject has an indwelling catheter or practices intermittent self catheterization * Subject has evidence of symptomatic urinary tract infection, interstitial cystitis, bladder stone, etc * Subject has an average total daily urine volume \> 3000 mL confirmed by patient diary * Subject has uncontrollable hypertension (SBP \>= 180 mmHg or DBP \>= 110 mmHg)