The standard treatment for overactive bladder starts with patient education and behavior therapies, followed by antimuscarinic agents. For patients with urgency urinary incontinence refractory to antimuscarinic therapy, currently both American Urological Association (AUA) and European Association of Urology (EAU) guidelines suggested that intravesical injection of botulinum toxin A should be offered. The mechanism of botulinum toxin A includes inhibition of vesicular release of neurotransmitters and the axonal expression of capsaicin and purinergic receptors in the suburothelium, as well as attenuation of central sensitization. Multiple randomized, placebo-controlled trials demonstrated that botulinum toxin A to be an effective treatment for patients with refractory idiopathic or neurogenic detrusor overactivity. The urinary incontinence episodes, maximum cystometric capacity, and maximum detrusor pressure were improved greater by botulinum toxin A compared to placebo. The adverse effects of botulinum toxin A, such as urinary retention and urinary tract infection, were primarily localized to the lower urinary tract. Therefore, botulinum toxin A offers an effective treatment option for patients with refractory overactive bladder.