We report two male patients with Parkinson's disease who developed compulsive risk-seeking driving behaviour as a result of self-administering high doses of L-dopa despite an adequate therapeutic response at lower doses. When L-dopa reduction was feasible, it resulted in cessation of unsafe driving. We believe that this impairment in driving performance, due to deliberate overuse of dopaminergic medication, should be included as a new behavioural phenomenon in dopamine dysregulation syndrome.