The first-ever Undiagnosed Hackathon was a groundbreaking event held by the Wilhelm Foundation, the Karolinska Undiagnosed Disease Program, and PhenoTips in collaboration with UDNI to solve medical mysteries and advance diagnostics for undiagnosed rare diseases. Nearly 100 healthcare professionals and researchers from 28 countries participated, working intensively for 48 hours to diagnose 10 families with undiagnosed rare diseases. This innovative approach to precision diagnostics highlighted the power of international, multidisciplinary collaboration and patient partnership, yielding promising results for patients seeking answers and benefiting the entire rare diseases community.