Researching tourist expenditure is of great importance since it represents a starting point when calculating possible economic effects. The aim of this paper is to identify the primary drivers of expenditure among active sport event tourists. Various socio-demographic and travel-related variables, as well as motivational factors, were included in the multiple regression analysis to explain total expenditure patterns of active sport event tourists in two sports, mountain biking and trail running. Although seven motivational factors were common to participants in both sport events, the motive related to nature was the only motivational factor that influences (negatively) overall spending of participants in trail running events while the factor related to stress relief positively impacts spending of participants in mountain biking events. The influence of socio-demographic variables on spending is event specific and should not be generalized to other events.