This joint submission to the OHCHR provides valuable inputs for preparing OHCHR's report on "human rights challenges in addressing and countering all aspects of the world drug problem", pursuant to resolution 52/24. The submission focuses on the impacts of drug policies on prison population, particularly regarding the rights to health and access to harm reduction in prison settings. It is co-signed by Harm Reduction International (HRI), Prison Reform International (PRI), European Prison Litigation Network (EPLN) PromoLex, and Health Without Barriers.