OBJECTIVES: To compare the costs of PD when using rasagiline and entacapone to treat patients that experienced motor fluctuations. METHODS: An 18-week randomised double-blind controlled clinical trial (RCT) LARGO, evaluating the safety and efficacy of rasagiline 1mg/d, entacapone 200mg with levodopa dosing or placebo, was conducted in levodopa-treated patients with motor fluctuations. Patients were then followed in a double-blind extension study (patients treated by active drug remain on their initial treatment). In some countries, patients were asked to participate in a pharmacoeconomic sub-study (PE). A cost analysis (in euros year 2003) examined resource utilisation, costs and caregiver burden of patients taking rasagiline versus entacapone. RESULTS: A total of 62 patients participated in each active treatment arm. Reduction in OFF Time after 18 weeks was comparable in each arm. Reduction in UPDRS total score after six additional months was similar in each arm. Both treatments were associated with comparable resource uses at each PE visit. Health care costs (except drugs) were 105€ for rasagiline and 88€ for entacapone. Total costs (health care + sick leave) were 107€ for rasagiline and 156€ for entacapone. Caregiver's Relative Stress Scale scores after four months of treatment were 34.5 for rasagiline and 33.9 for entacapone and 37.5 and 33.9, respectively, after 6 additional months. Difference between treatments in total caregiver's time on the entire period (9 months) was 34.9 hours in favour of entacapone. None of the differences were statistically significant. CONCLUSIONS: Resource use was lower than in routine population. Treatment with rasagiline and entacapone results in similar resource use and caregiver's burden. This is in line with the comparable efficacy of both treatments on motor fluctuations and activities of daily living. Thus, costs of treatments will have a clear influence on the total healthcare costs difference between both treatments.