Background: The present study explored the relationship between the pulmonary functions and exposure to cotton dust. Pulmonary function tests i.E. forced vital capacity (FVC), forced expiratory volume in first second (FEV1), and peak expiratory flow rate (PEFR) were recorded in 64 non smoker cotton ginners. The data on pulmonary function test for healthy Pakistani population from previous studies was used as control. The follow-up study for lung function testing on the same cotton ginners was conducted from 1999 and repeated yearly up to 2005. Because of cotton dust exposure, cotton ginners showed a significant decline in their pulmonary function (P