The theory behind the use of physical therapies (electrical stimulation or pelvic floor muscle [PFM] training with or without biofeedback) for overactive bladder is to (1) inhibit detrusor muscle contraction by voluntary contraction of the PFMs at the same time as the urge to void; and (2) prevent sudden falls in urethral pressure by a change in PFM morphology, position, and neuromuscular function. Few trials have evaluated the effect of PFM training on symptoms of overactive bladder. Most studies are flawed because they include several diagnoses and treatment modalities in the same intervention. Because of the lack of evidence, no firm conclusion can be drawn on the effect of PFM exercise on overactive bladder. There are some initially promising results, but there is still a need for high-quality, randomized controlled trials on the effect of PFM training on the inhibition of detrusor contraction in human beings. The efficacy of PFM training in combination with other treatments, such as pharmacotherapy, also requires investigation.