Joint submission by Harm Reduction International, the European Prison Litigation Network (EPLN), and Promo-LEX to the UN Special Rapporteur on extrajudicial, summary or arbitrary executions on “practices for the investigation, documentation and prevention of deaths in custody in the criminal justice context”. The submission focuses on deaths in custody of people in detention because of drug-related offences and/or with a history of drug use, and on deaths classified as ‘drug-related’. Primary attention is paid to gathering and availability of data; and policies and practices aimed at, or which could have a significant impact on, the prevention of such deaths. Information is also included on widely observed flawed in processed and measures for prevention of deaths, particularly suicides and transfers of seriously ill patients.