The chapter elaborates on the use of Botulinum toxin (BOTOX) in the management of overactive bladder. BOTOX is a potent neurotoxin derived from Gram-positive anaerobic spore-forming organism, Clostridium Botulinum. Type A (BOTOX) is currently used for the management of overactive bladder symptoms caused by detrusor overactivity and for the patients who have not responded to the conservative management. There are several evidences to support its use for patient with overactive bladder symptoms. Adverse events are only few and serious events are rare. The operative procedure is simple using a cystoscope. The beneficial effect of BOTOX would last up to 6–9 months and a repeat injection may be necessary.