Background: Breast cancer is the most commonly diagnosed cancer in women across the world. The majority of women diagnosed with the disease undergo surgery. Many patients suffer from upper limb impairments that result from mastectomy may interfere with some women's ability to resume normal physical function lead to significant psychological morbidity e.g low self-esteem. The basic goal of nursing care for patients who have had a mastectomy is to return the patient to normal life in the shortest period of time with the fewest problems. The aim of the study: to evaluate the effect of early upper limb exercises on reducing its disabilities and improving self-esteem among mastectomy patients. Research design: Quasi-experimental research design was utilized in the current study. Subjects: A purposive sample including (60) female adult patients were included in the current study. Setting: This study was carried out at oncology center in Minia city. Tools of data collection: Three scales were standardized and one tool was utilized to collect data:1-Bio sociodemographic characteristics and Structured interview schedule;2- Educational Information and Training Practices for Post-Mastectomy Exercises;3-Disabilities of the Arm, Shoulder and Hand Scale(DASH);4-Muscle Strength Scale;5-Rosenberg Self-Esteem Scale. Results: There were highly statistically significant differences between study and control groups regarding upper limb function, muscle strength and self-esteem in 1^st, 2^nd, and 3^rd observations post-mastectomy. Conclusion: The study findings concluded that upper limb exercises post mastectomy reduced upper limb disabilities in the study group. Also, it was found to increase and improve their muscle strength and self-esteem. Recommendations: Based on the research findings the researcher recommended applying upper limb exercises post mastectomy had a positive effect on patient's upper limb disabilities. The in-service educational training program that illustrates purposes and benefits of early post mastectomy exercises is very important.