Breast cancer is the most frequent diagnoses of cancer and there is evidence which suggest that it’s progression is determined by, in addition to biological, certain psychosocial factors like optimism, health locus of control, social support and satisfaction with hospital care. The mentioned constructs are additionally relevant for the patient’s mental adaptation and coping, so the goal of this research was to examine their predictive value in explaining stress, anxiety, depression and life satisfaction among women with breast cancer, along with biological factors such as age, cancer stage and type of surgery. A total of 181 women with breast cancer (M = 51.03, SD = 11.07) participated in this research through the Google Forms platform. In addition to sociodemographic data and data regarding their breast cancer, participants also filled out the Revised Life Orientation Test, Multidimensional Health Locus of Control Scale, The Social Support Scale, EORTC IN-PATSAT32, The Lauri Life Satisfaction Measurement and The Depression, Anxiety and Stress Scale. Statistical analysis revealed that optimism is a significant positive predictor of life satisfaction and negative predictor od depression, anxiety and stress among women with breast cancer. Furthermore, a locus of control that exhibits the individual’s belief that others have control over his health has shown to be a negative predictor of life satisfaction and a positive predictor of depression and stress. Social support positively predicted life satisfaction while ratings of negative COVID-19 impact on illness coping positively predicted depression and anxiety. Further analyses determined that there was no difference among women with breast cancer in life satisfaction, depression, anxiety and stress depending on their stage of cancer, type of surgical procedure and time of diagnosis in regards to the COVID-19 pandemic. Finally, the implications of this research along with it’s limitations and suggestions are reviewed within the discussion of this thesis.