There are about 2 million men in South Africa living with HIV who are not on treatment. How do we engage with this ‘hard-to-reach’ demographic and move them onto treatment? Matchboxology is the lead HCD partner on an innovative 3 year Gates Foundation Men’s project with PSI and Ipsos Research to better understand, serve and motivate South African men who haven’t actively engaged with current and previous HIV prevention and treatment initiatives (last mile clients) and to develop and testing initiatives for anti-retroviral (ARV) drug uptake and adherence. The Matchboxology team has worked with PSI and Ipsos to engage a local advisory committee of 20+ implementers and national/provincial Ministry departments throughout the project. Matchboxology worked in partnership with IPSOS to interpret field data from their landmark segmentation research and then designed and fielded collective solutioning and prototyping workshops across two provinces with key typologies. Outcomes from the workshop were refined into 10 prototypes and field tested 6, the most promising of which is in PSI supervised pilot study now, gathering final evidence to support adoption and scale up by local implementers and the Department of Health.