The prison building designed by Toricelli in the form of a medieval castle was being built from 1834 to 1864 and the project was preserved in the Historical Archive of the Russian State in St. Petersburg, some documents on which having been published in this article for the first time. Despite its rough appearance, the prison castle is imposed from a typological point of view where Toricelli was one of the most successful “romantic” architects of the first half of the 19th century. Chisinau Penitentiary Castle is an architectural monument, which is an important page in the history of the city and contributes to its originality. It needs to be protected from demolition even if there is already an apartment house project that is about to be built on its location. Taking into consideration that there is already a new prison and prisoners will be transferred there in the nearest future, the castle building can be preserved, becoming a very important and attractive historical sight.