Bladder function of patients with Parkinson's disease alters significantly: the majority of patients have overactive bladder (urinary urgency/frequency) with little or no post-void residuals. This seems to be the result of an altered brain–bladder relationship, as in Parkinson's disease, the frontal-basal ganglia D1 dopaminergic circuit that normally suppresses the micturition reflex is altered. The pathophysiology of the bladder dysfunction in Parkinson's disease differs from that in multiple system atrophy; therefore, it might also aid in differential diagnosis. The effects of levodopa, the major drug to treat motor dysfunction, on the bladder in Parkinson's disease vary significantly; therefore, add-on therapy is often required. Anticholinergic drugs are the first-line treatment, with particular care for cognitive function in elderly patients. The second-line treatment includes serotonergics drug, desmopressin and others. Newer modalities include deep brain stimulation that improves the bladder in Parkinson's disease; and botulinum toxin is promising, particularly in difficult cases. These treatments might be beneficial in maximizing the patients' quality of life.