We undertook a retrospective analysis of deaths that took place in prisons in Milan between 1993 and 2017, by identifying cases from a total of 24,101 autopsies that were performed at the Section of Forensic Medicine of the University of Milan. From the archives of this institution, we found 227 autopsy reports relating to deaths that had taken place in one of Milan’s three detention facilities. These deaths were divided into two types: natural deaths ( n=135; 59.5%) and violent deaths ( n=92; 40.5%). The groups have different characteristics: while natural deaths mostly resulted from cardiovascular diseases, suicides were mainly the result of hanging. Further, people who died by suicide often had a history of psychiatric disease and/or drug abuse, and over a quarter of them had previous suicide attempts and/or had declared suicidal intentions. This study confirms the need for good quality healthcare services for prisoners, given that they remain a population at high risk of early death.