The science fiction society SFera from Zagreb is the main organizer of the three-day convention named SFeraKon. The society was founded in 1976 in Zagreb and since then has been continuously operating as a non-profit, volunteer based cultural organization in the area of the city of Zagreb and the Republic of Croatia. SFeraKon is the oldest and largest Croatian convention that gathers fans of science fiction, fantasy, horror and related genres. SFeraKon is considered the largest in several categories: number of visitors, number of program series, number of exhibitors and lecturers. Through more than 4 decades, SFeraKon has become one of the largest European SF conventions and the largest in Central and Southeastern Europe. It is important to emphasize that SFera is a non-profit association that receives most of its funding from the city and state and through private donations, which is an extremely important factor in creating a future marketing strategy. What unites all members and volunteers of the society is the love for the same field and the desire to promote science fiction and related genres. The author of this paper started visiting SFeraKon, and later joined the SFera union and became one of the organizers of the convention. With regard to the studies, she saw how important marketing is in the organization and realization of a convention. The paper analyzes in more detail the work of the SFera society as well as the SFeraKon convention itself, as well as the marketing activities that are currently being carried out and which are necessary for the promotion of the event itself. Based on past events, the author brings forward proposals for the future through marketing mix, market segmentation, SWOT analysis and analysis of past marketing activities. Based on all the analyzes carried out, the author draws a conclusion in which she suggests improving the current marketing strategy.