A prerequisite for realizing the demand for public passenger transport is the existence of its potential which represents the population of a city, region or state. The number of inhabitants has a direct impact on the demand for transport. The paper deals with examining the relationship and dependence between the population demographic development and the demand for public passenger transport. Not only in Slovakia but also in Europe and in the world, the main problem is the ageing population. The changing age structure of the population changes requirements, demands and habits of transported population groups. A gradual increase in the holders of cards of a person with severe disability or a person with severe disability with accompaniment can be observed in Slovakia in recent years. This group of the population has also a very strong impact on the demand for public passenger transport. The dependence between individual variables is examined in the conditions of the Ţilina self-governing region.