Background: Yogic breathing practices have been ancient measure ensuring beneficial physiological responses in healthy individuals. Amongst various yogic practices, OM chanting may prove to be an advantageous respiratory exercise for conditions like asthma, COPD etc. Combination of A, U (O) and M, i.e., OM is one of the fundamental symbols used in the yoga tradition, which symbolizes the three states of consciousness i.e., waking state, dream state and deep sleep respectively as per ancient Indian philosophy or metaphysics. The present prospective study probed the effect of OM chanting in improving pulmonary functions and/or perception change for shortness of breath in patients with mild to moderate Chronic Obstructive Pulmonary Disease. Methodology: This prospective study included 30 mild to moderate stable COPD patients who were randomly allocated to two different study arms– one receiving the conventional pharmacotherapy for COPD and the other group was subjected to protocolised OM chanting as an add–on to the conventional pharmacotherapy. Both the groups were assessed for pulse rate, SpO2 and then subjected to 6 minute walk test (6MWT) and assessed for FEV1 (Post bronchodilation), SpO2, pulse rate at both baseline and at the end of 3 months. Anxiety was evaluated using State Trait Anxiety Inventory at both specified intervals. Results were statistically analysed. Results: Non–significant increase in FEV1 % and decrease in pulse rate changes in 6 minute walk test were noted in OM chanting group. No changes in SpO2and 6 minute walk distance were noted in either group. Significant decrease in anxiety scores in both state anxiety and trait anxiety domains and decreased perception of shortness of breath were noted for those in OM chanting group. Conclusion:OM chanting in addition to conventional pharmacotherapy may be effective in decreasing perception of shortness of breath (as per visual analogue scale) in mild to moderate COPD, that can be explained by practice of slow deep breathing instead of rapid shallow breathing during this yogic breathing techniques thereby causing decrease in hyperinflation. However the effect may be more prominent on prolonged intervention, which mandates further research.