<b><i>Background:</i></b> Undisclosed sexual infection risks are the main reasons for transfusion transmissible infections in German blood donors that have qualified for donation by donor health interviews and questionnaires. Until now, data about compliance with deferral criteria were only available from post-donation interviews with infected donors, and information about the proportion of donors which did not disclose (sexual) risks at the donor health questionnaire was not available. <b><i>Methods:</i></b> A prospective nationwide anonymous online survey was conducted to investigate compliance of whole blood donors with deferral criteria for sexual infection risks. Twenty-one blood establishments which represent 80% of the regular whole blood-donor population invited all donors which donated blood during an 8-week period between January and March 2020. <b><i>Results:</i></b> 14,882 participants completed the questionnaire. A relevant proportion of non-compliance was shown (3.0%, 95% CI: 2.7–3.3%) – with male donors being non-compliant significantly more frequently than females (3.5% vs. 2.2%, <i>p</i> &#x3c; 0.001). A quarter of the non-compliant men were MSM (0.9%, 95% CI: 0.7–1.1%). Non-compliance was strongly associated with the perception that questions about sexual risk exposures are too private. This is in line with the finding that a large proportion of donors (21%) refused to answer at least one question about sexual infection risks. <b><i>Conclusion:</i></b> The presented data, collected for the first time, is suitable for assessing the impact of changes in the donor selection process. Donor’s limited willingness to provide detailed information about sexual risk behaviour has to be kept in mind when further strategies for fair appraisal of individual sexual infection risks will be discussed.