This paper intends to deepen the analysis of the relationship between adult mortality and socio-economic status during the course of Italian health transition. Our research aims to answer a complex and unresolved question that can be formulated as follows: Italian mortality decline has been chacterized by a process of convergence, stability or divergence in SES differentials? The absence of a shared view on this matter is probably the consequence of the different temporal phases until now analysed, but it could be also the result of the diversified processes leading to mortality decline in Italy. This paper addresses this complex subject on the basis of two nominative datasets for the communities of Alghero (1866-1935) and Resia (1790-1999), reconstructed at the individual level, including a large variety of information, based on civil and parish records of birth, death and marriage, as well as other sources, like military registers. The first is a seaside Sardinian community, Resia, on the contrary, is a mountain village in the Friuli region. The two very far and different territorial contexts may provide useful insights for understanding the complex puzzle that describes the decline in adult mortality in Italy between the nineteenth and twentieth century.