Background: Quality of life of the modified radical mastectomy patients are greatly influenced by the surgical procedure as well as other treatment modalities like radiation therapy and chemotherapy. The aim of the study: The study aimed to determine the quality of life for the client with modified radical mastectomy. Research design: Descriptive design utilized in carrying out this study. Subject: A Convenient sample composed of 100 adult women admitted to the oncology department at the outpatient clinic of Baheya hospital. Tools: Interviewing questionnaire to assess demographic data of the women, knowledge assessment sheet about modified radical mastectomy, women practices after modified radical mastectomy, women's health problems after modified radical mastectomy and quality of life scale. Results: 40% of the studied women had satisfactory knowledge regarding modified radical mastectomy, 72% of the studied women had unsatisfactory care after modified radical mastectomy and 81% of the studied women had poor quality of life. Conclusion: Based on the study finding it concluded that, there is a statistically significant difference between the quality of life of studied women with modified radical mastectomy and their knowledge, practices toward the care related to modified radical mastectomy. Besides, there is a statistically significant difference between the quality of life of clients with modified radical mastectomy and their health needs and problems. Recommendation: Develop a health education program for women after mastectomy and their family management of the psychological & physical problems of chemotherapy that allows patients to base their understanding of cancer on sound information and misinformation.