The overactive bladder, according to the original definition by International Continence Society refers to the storage phase of the bladder and is diagnosed by urodynamics. The overactive bladder is a medical condition referring to the symptoms of frequency and urgency, with or without urge incontinence, in the absence of local pathology or metabolic factors that would account for these symptoms. The definition of overactive bladder needs clarification, which would help to overcome the current confusion. Possible neurological, muscular, and metabolic causes have been proposed but in many cases the exact causes remain unclear. The diagnosis depends greatly on a detailed history, clinical examination, and urinalysis. Urodynamic evaluation is indicated when neuropathy is suspected, and the treatment may be unsuccessful without exact knowledge of patients' state. It can be treated conservatively by bladder training, physiotherapy, and drugs alone or with combination. For refractory cases neuromodulation, denervation techniques, and bladder augmentation or substitution can be used with good results.