This article focuses on Sismondi's role in the development of Italian political thought in the long term. We argue that the scientific community's interest began with the publication of the Nouveaux Principles, which were regarded as a manual, but ended following Francesco Ferrara's renewed advocacy. The study of Sismondi in Italy did not proceed from the debate on the law of outlets, which was deemed too "theoretical", and found no champions—as it had in France—among socialist theorists. It focused, rather, on ideas relating more to practical issues of immediate use: state intervention in the economy, seen as the principal novelty in comparison to the prevailing paradigm, and the agricultural economic model. This essay suggests that Sismondi's influence was short-lived and intermittent; indeed, whilst during the liberal era the economic classics were not interpreted via his work, his theory of economic crises was only rediscovered in the 20th century.