This paper presents the epidemiological analyses based on the first 5 years of activity of the Mesothelioma Registry of Liguria (REM). REM is a population-based cancer registry specialized in the study of both the incidence and etiology of primary pleural and peritoneal mesothelioma in Liguria (Italy). The REM completes normal clinical information with occupational and environmental anamnestic data in order to identify working and living areas at risk for asbestos-related pathologies. The REM started its activity in 1994 describing the incidence of pleural mesothelioma (PM) exclusively in the population resident in the city of Genoa (660,000 inhabitants); since 1996 the REM has studied the entire Liguria Region (1,640,000 inhabitants), where nearly 120 new cases of PM are diagnosed annually (20% are women). In the city of Genoa, between 1986-1987 and 1997-1998, PM crude incidence rate rose from 13.8 to 26.7 per 100,000 males over 40 years old. From 1994 to 1998 the REM registered 495 new patients with histologically (62%) and cytologically (9%) confirmed diagnosis of PM. 54% of them were immunocytohistochemically evaluated. Occupational information has been gathered for 248 subjects, i.e., 61% of cases with sure or probable diagnosis of PM. For 126 patients, occupational asbestos exposure (direct, indirect or only presence in the workplace) was identified on average 40 years before diagnosis. In particular, asbestos exposure was documented in shipyards, docks and cargo handling settings, building trades, iron and steel industries. Interestingly, during the same period (1955-1960), a large fraction of subjects without proved or declared direct asbestos exposure claimed to have worked in the same occupational settings. This suggests a possible unconscious indirect exposure to asbestos fibers in the workplace.