The aim of the study was to assess the reliability of the indicators of dose and effect in the health monitoring of asbestos exposed workers. In 49 cases out of 158 studied workers (31%) asbestos-related diseases were diagnosed following ATS criteria (2004). Using nonparametric statistical methods (permutation tests) 6 variables were analyzed with respect to asbestos-related diseases and working sectors, demonstrating a difference in the concentration of amphiboles (p < 0.01), greater in patients with asbestosis and workers involved in asbestos removal from railway carriages. There was not a correlation between mesothelin and amphiboles, chrysotile and total fibers concentrations (Spearman test).