Aim of our present study was to evaluate the effect of AC on pulmonary functions in healthy persons who routinely use AC, like bank employees and compare them with normal healthy volunteers who do not use AC. A comparative study covering a total of 100 subjects divided into two groups (Group-A and Group-B). Group-A (Cases)consisted of 50 healthy male subjects exposed to air conditioner in their work place namely Bank offices for a period of 7to 8 hr for 5 days a week over a period of two consecutive years. Group-B (Controls)consisted of male subjects working in the Higher Education Department who were not exposed to air conditioner during their work for last two years.In the present study, there is a significant difference between Group A and Group B with respect to FVC as p= 0.0001. Also, there is significant difference between Group A and Group B with respect to FEV1 as p= 0.001. A significant difference was seen between Group A and Group B with respect to FEF25-75% as p=0.0001.Exposure to air conditioner in bank employs leads to significant decrease in pulmonary functions as compared to non-air conditioner users. The inhalation of dry cold air causes both small and large airways obstructive lung disease, as is reflected by the decreased parameters like FVC, FEV1, FEV1/FVC ratio, FEF25-75%, PEFR and MVV.