The study aims at assessing whether occupational exposure to Brac limestone, which contains a minute amount of silica, induces disorders of ventilatory capacity. It included 71 male workers employed in a stone saw-mill and 134 controls. The ventilatory functions VC, FEV1, FEV 1% VC, MEF25, MEF50 i MEF75 were examined, and the values analysed in respect to smoking habit. Variance analysis established a homogenous distribution of VC parameters, while others were heterogeneously distributed. This can be explained by smoking habit as assessable factor, and not by exposure to limestone dust. It is assumed that the production of Brac limestone in the stone saw-mill does not cause disorders in ventilatory function.