Due to the aging of the society and thereby a reduction of the donations of young people and additionally stricter approval requirements imposed by the Austrian Blood Safety Act, blood donation services face increasing challenges in securing the long-term blood supply. In order to counteract the reduced donation volume, regular donors play a central role in maintaining the blood supply, and thus a successful donor retention is of vital importance. For this reason, the aim of this master thesis is to identify which factors influence the donor retention of Styrian blood donors. In addition, barriers are explored, which prevent one-time blood donors from further donations. For this purpose, data concerning the blood donation experience, the incentives to donate, the means of communications and the donor retention were collected using guideline interviews from a sample of Styrian blood donors. They were analyzed using SPSS and MAXQDA. In the evaluation, a distinction was made between one-time donors and regular donors. It was found that the donation frequency, the number of temporary deferrals (donors were not allowed to donate), donation-related physical reactions, satisfaction with the organization, age and sex have an influence on donor retention. The greatest barrier was a low involvement. These results lead to a better understanding of the blood donor behavior in Styria and show blood donor organizations measures for encouraging retention.