Forced vital capacities (FVC's) and forced expiratory volumes in one second (FEV1.0's) of 26 pneumoconiosis patients were checked at admission and were followed up for 10 months through hospitalization. FVC's and FEV1.0's were slightly improved in 10 months after admission. The improvement of FVC's was statistically significant. In the group of large opacities in chest radiographs, FVC's and FEV1.0's were lower than those values in small opacity group at admission but improved more progressively. Similar finding was noted in the group of emphysema; those values were lower at admission but improved more progressively than those of non-emphysema group.