Hypersexuality is a known, though not frequently publicized, behavioral disturbance in patients with Parkinson disease. Hypersexuality has been associated with dopaminergic drug therapy. We describe a patient with Parkinson disease who presented with compulsive hypersexual behavior. Lowering of dopaminergic drug doses was of minimal behavioral benefit but was not well tolerated because of worsening of motor function. A trial with donepezil led to significant amelioration of the compulsive behavior without adverse motor effects.