For Parkinson's disease, the choice of the initial treatment is essentially between L-Dopa and dopaminergic agonists. Selegilin, anticholinergic and amantadine can be used for subjects with moderate symptoms. The first French consensus conference, held in 2000, elaborated decision-making rules which take into account both the age and disease severity. The aim of our study was to evaluate the impact of these recommendations on treatments prescribed for de novo parkinsonian patients in the Nord-Pas de Calais area, comparing initial prescriptions before and after the conference. Three groups of 50 patients whose diagnosis of Parkinson's disease had been establish in three periods (1985-1992, 1993-1999, and after July 2000, date of the national publication of the consensus) were constituted. For these 3 groups, the initial treatment complied with the 2000 recommendations for 58, 84 and 82 percent of the patients respectively. The prescriptions of agonists increased progressively while the prescriptions of L-Dopa decreased for younger patients, in concordance with the consensus, but also for older patients, in opposition with the recommendations, though without any increase in the incidence of side effects. The non dopaminergic treatments were almost discarded as initial treatment. Prescription habits have gradually changed over the past 10 years. Changes were linked to the elaboration of the national consensus conference guidelines and to the apparent desire to decrease L-Dopa prescriptions.