Parkinson disease (PD) is a movement disorder characterized clinically by the variable combination of rigidity, bradykinesia, rest tremor and postural instability. Usually postural instability is a late-onset manifestation and is frequently associated with axial manifestations and with a poor prognosis. We report a 67-year-old female with orthostatic tremor as the etiology of her postural instability. The patient was treated with increasing doses of clonazepam, reaching 2 mg/day, and levodopa. There was an improvement of postural instability with a good response of parkinsonian symptoms.