The hypothesis that weight on the chest may diminish the compliance of the chest wall and affect chest wall dynamics guided this research. Few previous studies investigated the possibility of increasing chest compliance and pulmonary function after reduction mammaplasty. The meager results available were contradictory. The aim of this study was to determine the relation between reduction mammaplasty and pulmonary function. Thirty-three adult female patients who presented for reduction mammaplasty were included in the study. Paired t test showed nonsignificant change in pulmonary functions after reduction mammaplasty. Pearson method of statistical analysis revealed a significant positive correlation between the total weight of breast tissue removed and pulmonary function, and a negative correlation between the total postoperative breast volume and the pulmonary function. The study concluded that the more the breast tissue weight removed and the less the postoperative total breast volume, the better the postoperative pulmonary function.