Abstract Background: Postoperative pulmonary complications are an important cause of morbidity following upper abdominal surgery and pulmonary function is doubtlessly affected after open abdominal surgery especially in elderly patients. Aim of Study: Tomeasure the effect of inspiratory muscle training as a prophylactic treatment from pulmonary compli-cations after abdominal surgery in elderly patients. Patients and Methods: Sixty patients with abdominal surgery, their age 60±. They were recruited from Kasr Al-Ainy Medical School. They were assigned randomly into two equal groups. Study Group (A): Included 30 patients subjected to inspiratory muscle training using threshold inspiratory muscles trainer device "TIMT", in combination with incentive spirometer and routine chest physical therapy program. Control Group (B): Included 30 patients subjected to incentive spirom-eter and routine chest physical therapy program. Treatment applied daily from postoperative day one and continued for two weeks. Pre and post study assessment ofpulmonary function (FVC, FEV1, FEV1/FVC and MVV), functional capacity (6min walk distance), dyspnea (mMRC score) and BODE index score. Results: This study revealed a statistical significant im-provement in (FVC, FEV1, MVV, 6MWD, mMRC and BODE index) post-treatment mean values favor of group A patients than in group B and a non-statistical significant improvement in FEV1/FVC between group A and group B at post-treatment. Conclusion: Inspiratory muscle training had a significant effect on pulmonary function, functional capacity and dyspnea, so this study support the importance of adding inspiratory muscle training using threshold inspiratory muscles trainer device into the postoperative physiotherapy program after abdominal surgery in elderly patients as a prophylactic treat-ment from pulmonary complications.