The purpose of this study was to evaluate respiratory effects of wet and dry hyperbaric chamber dives to 0.6 MPa ambient pressure in healthy males. There were 19 and 22 subjects who participated in two series of dives with a bottom time of 15 min and decompression times of 28 and 17 min, respectively. Airways conductance, residual volume, forced vital capacity, forced expiratory volume in 1 sec, mid expiratory flow at 25, 50 and 75% of FVC, and diffusion capacity for CO were measured before the dives, after 3 h, and after 24 h. Multivariate analysis of covariance revealed no statistically significant effects of time or the interaction between time and dry or wet environment on the measured lung function parameters. These findings suggest first that even deep air dives may not necessarily affect pulmonary function, and second, that factors related to the particular wet environment do not seem to contribute to lung function changes after dives.