Data on the natural long-term course of Parkinsonʼs disease (PD) remain sparse. The aim of this study was to describe the evolution of the functional disability and the response to dopaminergic therapy in patients with PD for many years. The files of 47 patients who had been diagnosed with PD more than 13 years previously were reviewed. Mean age at disease onset was 47 ± 9 years, and mean disease duration was 23.5 ± 9.8 years. Levodopa treatment was initially effective in 95% of the patients but the response decreased with time. At the end of the follow-up period, end-stage disease, i.e. Hoehn and Yahr (H&Y) stage 5 was documented in 45% of the patients. In patients with response fluctuations H&Y stage was graded 5 in 53% of patients in the “off” period and in 27% in the “on” period. In patients without response fluctuations H&Y stage was graded 5 in 23% of patients. Two patients had stage 2 disease (minimal disability). In conclusion, PD has a chronic progressive course, although most patients do not reach end-stage disease. The effect of l-dopa treatment decreases over time, but is not lost completely.