Aim of the research is to provide a sketch of the criminal justice history in the Republic of Lucca between the sixteenth and the eighteenth centuries. We begin with a recognition of the different bodies of law of the period, then exploring the judicial system of Lucca and finally with the examination of the “ordo procedendi” and its evolution in the modern age. From the analysis, a significant role appears to be played by the legislation in criminal field, certainly related to the power held by the `Maggior Consiglio', the branch holding legislative power. Concerning procedural aspects, this study confirms the phenomenon of gradual formalism growth, already noticed in other Italian contexts in modern age.