The historiography of epidemics and crime suggests that we might find effects of plague on criminal behaviour in the years of the Black Death and its aftermath, yet this question has not been systematically investigated by late medieval historians. For the first time, a continuous series of trial records covering the 1340s – for the city of Bologna – is here analysed, and the issue of a ‘breakdown in law and order’ is addressed. The particular patterns of criminal prosecution are revealed and explained, including unusual and unexpected features of continuity in 1348, and surprising developments in the years following, with changes in political context and judicial procedures outweighing any ongoing effects of plague.