BACKGROUND: The successful introduction of prophylaxis with anti-RhD immunoglobulin has resulted in a significant decline of pregnancy-related RhD immunizations but also has decreased the availability of naturally immunized women as (new) anti-D donors. An influx of new donors is necessary to maintain a sufficient pool of anti-D donors. We investigated motivators, barriers, and predictors for anti-D donorship in RhD-immunized women. STUDY DESIGN AND METHODS: A mixed-methods design was applied, including focus group discussions and questionnaires. Two focus groups (including 11 women) served as input for the questionnaire. RESULTS: In total, 47.6% of 750 anti-D donors and potential donors completed the questionnaire (50.4% donors; 38% nondonors; 11.6% former donors). Almost 70% of the nondonors would have become donors if they had known about the possibility. Travel time investment was reported as a disadvantage; one-half of donors mentioned no disadvantages. Motivators for anti-D donorship were “doing something in return” (31.2%) and “preventing others having a sick child or losing a child” (33.9%). In multivariable analysis, living single (odds ratio, 5.8; p = 0.02) and living partnered without resident children (odds ratio, 7.9; p = 0.03), compared with living partnered with children, were predictors for anti-D donorship. Not being registered as an organ donor (odds ratio, 0.25; p < 0.001) predicted that the individual would not be an anti-D donor. CONCLUSION: The main barrier for anti-D donorship was a lack of knowledge. Positive predictors of anti-D donorship were living without resident children, altruism, and being registered as an organ donor. A blood bank should develop targeted recruitment strategies with a focus on spreading knowledge about anti-D donorship among RhD-immunized women.