Drug therapy for overactive bladder (OAB) is associated with improvements in symptoms and quality of life, but the short- and long-term adherence and persistence is suboptimal. In this review we outline methods of measuring, and factors affecting, adherence to pharmacotherapy in patients with OAB. Clinical practice suggests that adherence rates reported in clinical trials are much greater than in real practice. Factors affecting adherence include psychological and social variables that might alter patients’ perception of the benefits of taking medication, and the effect of comorbidity and polypharmacy. Whilst there is some evidence that lack of efficacy and side-effects are contributory, these additional factors are also important.