The presence of ophiolites in areas of Basilicata, where there have been reports of mesothelioma in farmers, is known. This study evaluates the increased risk of exposure to tremolite in carrying out agricultural activities. Cases of mesothelioma occurred in farmers with unknown exposure to asbestos have been selected and assessed the employment in areas contaminated by tremolite. Personal samplings were conducted in a group of farmers employed in these areas and a group of subjects used in activities that do not involve contact with the ground. For the 5% of cases of mesothelioma in the lucan register emerged exposure to asbestos exclusively in farming activities in areas at tremolite risk. The analysis of the samples showed the presence of personal fibers of tremolite in 2/3 of the cases. In 60% there was an overcoming of the natural limit of 2 ff/l, with a peak up to 23.6 ff/l. The study shows that the risk of exposure to tremolite in agriculture is significantly higher than natural exposure.