Aging is associated with the onset of respiratory symptoms and problems and a negative impact on pulmonary indices. Physical activity is considered as a treatment and prevention line for improving respiratory function and muscle strength involved in breathing. It seems that no study has been done on the effect of yoga breathing exercises (pranayama) on pulmonary function indices in elderly men. Objective: Considering the role of physical activity in improving lung function, the aim of the present study was to investigate the effect of 8 weeks of pranayama on pulmonary function in elderly men. Materials and Methods: In this study, 24 elderly men with an age of 60-70 years were selected by purposive sampling method and divided into two groups of control and breathing exercise (N=12). The exercise program included 8 weeks of pranayama with 3 sessions per week. The pulmonary function test included lung volumes, which were evaluated before and after the intervention. Data were analyzed by analysis of variance method using SPSS21 at a significance level of P ≥ 0.05. Results: The results showed that 8 weeks of pranayama significantly increased (P = 0.001) FVC and (P = 0.001) FEV1 in the post-test of the experimental group. Also, FEV1/FVC increased in the post-test of the experimental group but was not significant (P = 0.878). In addition, no significant change was observed in the measured variables of the control group compared to the pre-test. Conclusion: pranayama, by strengthening the respiratory muscles, can probably improve lung function in elderly men.