This article aims to understand norms and values pertaining to the definition of just wages in early modern Italy. The starting point is the treatise by the jurist Lanfranco Zacchia, De Salario seu Operariorum Mercede, which appeared in the mid-seventeenth century and represented the first attempt to collate a set of rules on wages based on the traditions of Roman and canon law. After a brief presentation of the treatise, I shall analyse the meanings and concepts of wages, and then consider the elements that determined the just wage. To understand how prescriptions were seen by individuals, I shall also compare them with information about court cases and rulings compiled by Zacchia in another book, the Centuria decisionum ad materiam Tractatus de Salario, and with the rest of the existing literature. Evidence from my comparison will allow us to understand the interaction and reciprocal influences between juridical thought and daily work practice, and underline the fact that wages were based on a complex system of norms and values where individuals, their social positions, skills, and experience determined the recognition of the just wage with reference to the local context.