The previous urodynamic definition of detrusor overactivity (DO) has been supplemented by a symptom-based description called overactive bladder (OAB). OAB affects a sizeable proportion of patients, most of whom remain untreated, despite the significant impact of their symptoms on their everyday lives. Anti-cholinergic drugs are the most widely used treatment for OAB and are active at muscarinic receptors in the bladder and in other parts of the body. Newer agents may be more bladder selective than older drugs and tend to be better tolerated by patients. Developing an effective, patient-driven way of assessing and managing OAB is essential for improving treatment and meeting the needs of a largely untreated population.