In order to determine primary health care providers' (PCPs) knowledge gaps on Parkinson's disease, data were collected before and after a one-hour continuing medical education (CME) lecture on early Parkinson's disease recognition and treatment from a sample of 104 PCPs participating at an annual meeting. The main outcome measure was the proportion of questions answered correctly by each PCP before the lecture. We measured the change in proportion of correct answers before and after the lecture (delta). Ninety-nine percent of the PCPs who attended the lecture returned the questionnaire. The level of knowledge on Parkinson's disease before the lecture was relatively low, particularly in management (61.4%) and diagnosis (34.4%). PCPs' perceived knowledge was not associated with the number of correct responses on management at baseline. Test scores significantly improved after the CME lecture. Our results show that PCPs' baseline knowledge of diagnosis and management of Parkinson's disease and self-perceived knowledge on this topic are relatively limited. Appropriately, United States reaccreditation programs do not only rely on self-perception. Longitudinal studies are needed to determine the impact of CME in knowledge retention and patient care in Parkinson's disease.