Abstract: The paper summarizes the results of the research executed in 2016 among 15 museums and exhibitions of different size in Budapest. The research involved deep interviews with museum leaders and observation of the institutes’ exhibitions and other activities. The aspects of the research were target groups, method of interpretation, interactivity, marketing, involvement of volunteers, etc. Four important factors seem to influence visitor numbers the most, such as location, historic building of the museum itself, general attribute of the topic treated and the level of interactivity. Results were analysed in the frame of new museology, a new paradigm, in relation with museum development and operation which have to be taken into consideration by all leaders in these attractions. Museums have the responsibility of sensitization of the public regarding the importance of different topics and the value of heritage, treated among the walls. If they do not accept the methods of interpretation fitted to new generations or to anyone living in the rushing world of the 21st century, then they won’t be able to attract enough visitors for their sustainable operation and for the fulfilment of their goals. Sustainability of museums was evaluated on the basis of environmental, economic and socio-cultural points of view. Mostly all factors, analysed during the research affect one or more of the abovementioned aspects of sustainability.