OBJECTIVES: PD-LID, a complication of L-Dopa treatment, is associated with inability to perform daily living activities, reduction in quality of life and increase in healthcare costs. Limited data are currently available on the burden of this disease. LIDIA describes medical and non-medical resource utilization and economic impact of PD-LID patients from payer and society perspective according to LID severity: mild (mAIMS score<8), moderate (mAIMS [8-12]) and severe (mAIMS>12) patients. METHODS: This observational, prospective, longitudinal, multicentre 6 month-study was conducted by French neurologists specialized in Parkinson’s disease (PD). PD patients taking L-dopa for at least 3 years were included, with PD-LID present for more than 3 months and for more than 25% of the time. RESULTS: 33 neurologists included 186 patients (mean 68 years old, 52% women) with mean mAIMS score at 10. PD-LID patients were mainly followed by their neurologists (96%) and general practitioner (GP) (84%) with more non-medical follow-up for severe patients. Almost 60% had at least one biological or radiological examination, only 31% required transport. All patients received L-Dopa (including 32% long-acting), and 69% dopaminergic agonists. Only 21% had at least one hospitalization and over 40% needed home layout and mobility equipment. Most patients (70%) were assisted by a caregiver (24h/week), 43% required external assistance (6h/week), 22% received an invalidity allowance. Total costs represent 35117€, 33640€ and 43739€ in respectively mild, moderate and severe patients (on average per patient/year). Non-medical costs (transportations, paid external help, caregivers time, mobility equipment, home layout) are the major cost drivers (80%), including caregiver help (70%), followed by medical (consultations, treatments,  hospitalizations)(15%) and indirect costs (allowances and work stoppages)(5%). CONCLUSIONS: The LIDIA study confirms that in this disabling disease, the economic burden is mainly supported by the patient family, with the payer part being 23%. Economic burden is greater in patients with severe dyskinesia.