This paper examines the length of stay of cultural tourists in a mountain destination, on the North-East of Italy. A microeconomic perspective of cultural tourism is provided, where the interest is to analyse the attitude of visitors regarding culture and their overall vacation. To this aim, visitors’ behavior to the South Tyrol's Museum of Archaeology in Bolzano (Italy) is analysed through survey data. Unlike similar studies, empirically, a zero-truncated negative binomial model is estimated as a generalization of a Poisson distribution. The analysis shows which are the main determinants that influence length of stay of cultural tourists. Nationality, age, employment, income, costs associated with the travel have an impact on length of stay. Specifically, variations in such factors correspond to variation in the span of the vacation that is also positively affected by the presence of the icemen Ötzi in the museum as well as by the presence of other cultural attractions. These findings provide an essential tool to manage heritage resources and plan the future tourism development around the Ötzi museum.