The Italian 19th century was a century of profound economic, political and social changes that brought about the formation of an independent state which was now in need of a unitary language. This historical and cultural background induced the development of the Italian lexicography that underwent a real revolution. This study aims to observe the course of the lexicographic revolution by identifying the salient features of the most significant dictionaries of the 19th century. The presentation of the major lexicographic achievements of the first and second half of the 19th century is followed by a comparative analysis of the structure of lemmas in four selected dictionaries:Crusca veronese from Antonio Cesari (1806-1811), Vocabolario universale italiano (il Tramater) (1829-1846), Dizionario della lingua italiana from Niccolò Tommaseo and Bernardo Bellini (1861-1879) and Novo dizionario della lingua italiana secondo l’uso di Firenze from Emilio Broglio and Giovan Battista Giorgini (1870-1897). The comparative analysis focuses on 5 dictionary entries from each of the aforementioned dictionaries in order to examine their role in the 19th century Italian lexicographic revolution.