Background: Previous studies showed that cancer significantly reduces the quality of life of patients. The purpose of this study was to analyze changes in the quality of life of women diagnosed with ovarian and breast cancer after surgical treatment followed by adjuvant cancer therapy. Methods: The study covered 220 women diagnosed with ovarian (n = 89) or breast cancer (n = 131) after surgical treatment followed by adjuvant cancer therapy (chemotherapy, radiotherapy, hormone therapy). The tools used to measure the patients’ quality of life were the standardized EORTC QLQ-C30 questionnaire, the QLQ-BR23 module for breast cancer and the QLQ-OV28 module for ovarian cancer. Results: The subjective assessment of the health and quality of life of the women was carried out using the EORTC QLQ-C30 questionnaire and the QLQ-OV28 and QLQ-BR23 modules. Women with breast cancer rated their health higher than women with ovarian cancer. The health assessment performed by the patients was not related to the type of cancer (p > 0.05). They experienced pain, dyspnea and weakness regardless of the cancer location. Moreover, women’s health status had a clinically significant impact on their family and social life, although no statistically significant differences were found between the two groups (p > 0.05). Whilst the patients with breast cancer rated their quality of life and health higher than the patients with ovarian cancer, the differences were not statistically significant (p > 0.05). Conclusions: Changes in the quality of life of women with breast and ovarian cancer concern the physical sphere, hobbies, fatigue/rest, pain, family and social spheres, and material conditions. It is necessary to support specialists at every stage of treatment of these patients, which may improve the results of the treatment and patients’ perception of health and quality of life.