The study aims to assess quality of sexual life among post mastectomy women. A descriptive exploratory study was utilized with a sample of (200) post mastectomy women who attend outpatient clinic of oncology center at Mansoura University after at least one year of mastectomy. Data were collected by using two tools, one for assessing socio demographic and clinical characteristics which developed by the researcher, the second for assessing the quality of sexual life and its developed by the researcher, . Results revealed that about two thirds (66 %)of the studied patients have unsatisfactory quality of sexual life, while the other third of them have satisfactory quality of sexual life and there is statistically significant relation between quality of sexual life, and age(P ≤ 0.001), the studied patients whose age is (30-40) years old have the high scores of satisfaction regarding their quality of sexual life with mean of (44.72), while the studied patients whose age is (41-50) years old have the low scores of satisfaction regarding their quality of sexual life with mean of (39.4). In conclusion, about two thirds of the studied patients have unsatisfactory quality of sexual life after mastectomy, Therefore, Comprehensive health educational programs for all women following breast cancer treatment in outpatients' clinics of oncology units include psychological, social, rehabilitation, and follow up, earlier recognition of sexual problems and active involvement for sexual health improvement program are recommended.