This study evaluated the prevalence and clinical characteristics of akathisia in a tertiary care Parkinson's disease (PD) practice, and assessed the agreement between investigators for the diagnosis of akathisia in PD, and the sensitivity and specificity of a brief patient questionnaire. Fifty-six consecutive PD patients completed an akathisia questionnaire and then were clinically evaluated for akathisia by two examiners blinded to the patient questionnaire. Overall, 45% of PD patients had akathisia as determined by clinical evaluation. Interrater reliability for the diagnosis of akathisia was high (K = 0.89). Patient self-report of restlessness agreed with examiner diagnosis in 89% of the patients. The presence of akathisia was associated with the severity and age of onset of PD. Symptoms most frequently affected the legs, and associated movements were suppressible for brief periods.