We report 6 patients with pathological gambling during pharmacologic treatment for Parkinson disease (PD). Four patients were treated with levodopa/carbidopa and dopamine agonist (DA), and 2 patients received DA monotherapy. We reviewed several published reports regarding pathological gambling and antiparkinsonian therapy and suggest that more advanced PD and antiparkinsonian combination therapy (e.g., levodopa/carbidopa and DA) increases the risk for development of pathological gambling behavior compared with monotherapy with either DA or levodopa/carbidopa.