Objective: To assess the state of care for insulin-dependent people with diabetes in detention in France in 2012. Methods: From November to December 2012, a questionnaire was sent to the health units (HUs) of correctional facilities. It aimed to assess the number of patients treated with insulin, the availability of supplies in cells, incidents related to cell confinement, and the medical care provided (follow-up, therapeutic education). Results: In total, 54.8% of the surveyed HCUs responded, representing 55.5% of the French prison population as of December 1, 2012. The observed prevalence of insulin-dependent diabetes in detention was 0.77%. Insulin injection supplies were permitted in cells in nearly 88% of facilities, and self-monitoring supplies in 90% of cases. Few incidents (suicide attempts, needle diversion, etc.) were reported, and no assaults. Conclusion: in 1999, in more than 60% of cases, medical supplies were not permitted in cells; insulin injections were administered by nurses in 90% of cases, which did not promote patient autonomy regarding their condition. In 2012, there was an improvement in access to care that allowed for the maintenance of patient autonomy, without an increase in the number of incidents. (R.A.)