Starting from a short review of the recent epidemiological studies available in the international literature concerning the association between silica, silicosis and lung cancer, the results of two mortality studies performed in Sardinia are reported. The first study concerns a 20-year follow-up of 1741 miners employed in 1973 in two metalliferous Sardinian mines. In the second study the cause specific mortality of 724 patients with silicosis, firstly diagnosed by standard chest x-ray between 1964 and 1970 in our Institute, has been analysed by a cohort study extended to December 31, 1997. The findings indicate that the slight increased lung cancer mortality observed in these cohorts, more than to the severity of radiological silicosis or to the entity of the cumulative exposure to crystalline silica dust in itself, was significantly associated to other risk factors as cigarette smoking, airflow obstruction and radon-daughters exposure in underground mines.