Our medical care relies on a safe, sufficient blood supply. This project, in partnership with the NZ Blood Service (NZBS), seeks to minimise risk to the blood supply while maximising blood donations. To maintain blood safety, NZBS excludes most gay and bisexual men (GBM) due to a risk of unrecognised HIV infection, but this unnecessarily prevents many low-risk GBM from donating. Many GBM view this as unjust, unscientific and out-of-date given new HIV prevention tools. Similarly, NZ’s HIV sector agencies need to understand who is most and least at risk so they can deliver interventions effectively. We will investigate unrecognised HIV and produce the first NZ data on attitudes and compliance with blood safety policy among GBM, the group posing the most risk to the blood supply and the most impacted by the blood donor deferral policy. Findings will inform the 2024 NZBS safety review and help HIV agencies end transmission.