No curative therapy is available for Parkinson's disease; therefore, one of the main goals of treatment is to control motor symptoms, often via the use of levodopa (also known as L-dopa). However, prolonged levodopa treatment in Parkinson's disease has been associated with the development of motor fluctuations and the occurrence of levodopa-induced dyskinesias (LIDs).To gain a clear, empirical understanding of the current real-world approach to treatment and patient outcomes associated with Parkinson's disease and LIDs.This study used a mixed methodology, combining a cross-sectional survey of neurologists practicing in the United States, a retrospective chart review of patients with Parkinson's disease and LIDs, and cross-sectional surveys of health-related quality of life (QOL) and physical functioning in patients with Parkinson's disease. The surveys included the 39-item Parkinson's Disease Questionnaire, the Unified Parkinson's Disease Rating Scale, the Parkinson Disease Dyskinesia 26-item Scale, and the modified Abnormal Involuntary Movement Scale (mAIMS). Survey and chart data were collected between May 2010 and July 2011. Descriptive analyses were used to evaluate the distribution of study variables, treatment patterns, patient QOL, and patient physical functioning.Data from 7 neurologists and from 172 patients with Parkinson's disease and LIDs were collected. Results from the physician survey indicate that prescribing patterns depend largely on the severity of LIDs, assessed via mAIMS. Most patients (88%) received pharmacologic therapy as first-line treatment for LIDs, with monotherapy favored in patients with mild LIDs and combination therapy in patients with moderate-to-severe LIDs. The mean time from the diagnosis of LID to the administration of first-line treatment for the condition was 10.7 months (standard deviation, 14.0 months). The study population reflects a mean time from levodopa initiation to the onset of LIDs of slightly more than 5 years, regardless of the levodopa dosage. Results from the chart review and the physician survey suggest a strong alignment in severity classification among the assessment scales used.These findings indicate that the diagnosis and the treatment of Parkinson's disease and LIDs are not optimal, because of the length of time from diagnosis to treatment, and because of the variability in treatment selection and response. Additional real-world studies are recommended to better understand treatment patterns, compliance with guidelines, and their potential impact on patient outcomes.