The Museum of Criminology was founded in1931 by the Minister of Justice Alfredo Rocco and was initially set up in the seventeenth century building of the Carceri Nuove (New Prisons) in Via Giulia and moved to the adjacent former juvenile prison in Palazzo del Gonfalone in1975. 

It originally consisted of three sections; the Museum was supposed to collect the objects of major relevance regarding criminality and make them available to scholars, from the instruments of torture to the material evidences. Therefore instruments of death, such as the imposing guillotines, and of di torture, such as the iron sarcophagi equipped with internal thorns and the cages shaped like a human body are exhibited. 

Next to them are arms and pistols used for famous crimes and also the peculiar red cloak of the most legendary executioner in Rome, Mastro Titta. In the nineties the theme-separation system was replaced by a historical-cultural itinerary divided in three periods. The history of the prison institution and of the penitentiary reform are also presented in parallel with the history of the evolution of crime.