Introduction: Post-mastectomy lymphedema is a chronic, debilitating disorder that is frequently misdiagnosed, treated too late or not treated at all, Lymphedema (LE) is an abnormal accumulation of protein-rich fluid in the interstitium leading to limb swelling, chronic inflammation and reactive fibrosis of the affected tissues resulting from damage to lymphatic circulation following surgery, chemotherapy and/or radiation therapy. The aim was to investigate the effect of shockwave therapy on the post-mastectomy lymphedema. Subjects and methods: Sixty female patients underwent modified radical mastectomy surgery or lumpectomy, chemotherapy and radiotherapy associated with unilateral lymphedema (stage 2, 3), into two equal groups; their ages ranged from 30-50 years. The study group received shockwave therapy 2 times/week for 6 weeks plus traditional physical therapy program (manual lymphatic drainage, circulatory exercises with elevation, shoulder ROM exercises and pneumatic compression therapy) 3times /week /6weeks. Control group received traditional physical therapy program (manual lymphatic drainage, circulatory exercises with elevation, shoulder ROM exercises and pneumatic compression therapy) 3times /week /6weeks. Evaluation procedures were carried out to measure the upper limb volume measurement, ROM of shoulder flexion, abduction and external rotation. Results: Post treatment results showed that there was a significant improvement difference in shoulder ROM and upper limb volume in both groups in favor of the study group.