The question of the role of physical activity in preventing disability in neurological diseases is the issue which is not in doubt. There is well known that physical activity in Parkinson`s disease and in Multiple Sclerosis patients is less than is the case in the general population.Numerous scientific studies have confirmed the low physical activity of people with PD and MS. Improving physical activity delays the progress of physical disability and has the effect on increasing the quality of life in those two diseases. In this paper an descriptive review of the literature devoted to the effect of physical activity on risk of PD and its impact on disability progression in PD and MS has been presented. The different recommendations for physical activity and different methods of assessment have been described.