Event tourism represents one of the important types of tourism, which can provide the opportunity to complement the tourist supply, to reduce the problem of seasonality, to preserve the specificities and create recognisability of local units and to stimulate its development. Here is necessary to apply suitable managing because events, such as festivals, can have positive and negative impacts. The aim of this thesis is to present the influence of festivals on the development of the local units. The main fundamentals in managing manifestations are shown, while festivals are elaborated in more detail. The concept of local community that connects common interests of the population of the local unit is explained and the role of the local community in the process of managing tourism development is analysed. The influences of the Outlook and Dimensions festivals are analysed in Štinjan and Pula, by using chosen economic indicators, data about accommodation, transport, media influence and broader influences on local community. The results of the survey about the local community perceptions of festivals are shown. It is determined that the success of the festival can be measured by benefits, but also with the acceptance of the local community that should be included in managing tourism development. The results of the analysis have confirmed the positive impacts while it is also necessary to timely recognize and prevent potential negative influences of the festivals.