Introduction: Each year, around 16,500 women in Poland are diagnosed with breast cancer, the second most common cause of death in women. In Poland, nearly 70,000 women live with breast cancer diagnosed within the last 5 years. Quality of life (QoL) research is particularly important in cancer patients, as it provides knowledge on their psychological and physical health, as well as the environment in which the patients function, all of which is essential to implementing multidisciplinary care involving the best use of the appropriate methods. Carrying the burden of cancer is a major challenge for patients. The strategy that patients use to cope with breast cancer significantly affects their quality of life. The purpose of the study is to assess the impact of coping strategies on the QoL in breast cancer patients. Material and Methods: The prospective study included a group of 202 women who had undergone surgical treatment for breast cancer at the Lower Silesian Cancer Center and who reported for follow-up appointments at the Oncology Clinic and the Surgical Oncology Clinic. For the study, we used the: EORTC QLQ-C30 cancer questionnaire, EORTC QLQ-BR23 module, Mental Adjustment to Cancer (Mini-MAC) scale, visual analog scale (VAS) for pain intensity, as well as the patients’ medical records, hospital records, and our own survey form. Results: The mean patient age was 53 years. Most patients had been diagnosed with cancer between one and two years before. In the women studied, there was a negative association between QoL and the choice of a destructive strategy for coping with cancer, and a positive one between QoL and a constructive coping strategy. Severe pain caused by the disease and its treatment significantly decreased the patients’ QoL in multiple domains. Conclusions: Patients choosing constructive strategies obtained higher QoL scores, while greater reliance on destructive coping strategies was associated with significantly worse QoL. In all functioning domains, higher levels of pain were associated with poorer QoL and more severe symptoms associated with the disease and its treatment.