['To assess the 24-h efficacy of tolterodine extended-release (ER) in patients with overactive bladder (OAB) and urgency urinary incontinence (UUI).', 'We conducted a post hoc analysis of a 12-week, placebo-controlled trial of tolterodine-ER in patients with frequency (> or =8 voids/24 h) and UUI (> or=5 episodes/week) for > or = 6 months. Seven-day bladder diaries were used to record diary endpoints; 24-h diary data were stratified by 6-h periods beginning at midnight.', 'Compared with placebo (508 patients), tolterodine-ER (507 patients) significantly and consistently increased volume voided per void and reduced UUI episodes and micturition frequency during each interval.'] Is the clinical efficacy of tolterodine extended-release maintained for 24 h in patients with overactive bladder?