Poor breast cancer–related quality of life is associated with flattened cortisol rhythms and inflammation in breast cancer survivors and women with advanced disease. We explored the associations of cancer-specific distress (Impact of Events Scale), mood (Profile of Mood States), activity/sleep (wake after sleep onset, 24-hour autocorrelation coefficient) and cortisol (diurnal slope) circadian rhythms, and inflammation (interleukin-6) with quality of life (Functional Assessment of Cancer Therapy–Breast) among patients awaiting breast cancer surgery (N = 57). Models were adjusted for differences in age and cancer stage. Distress and mood disturbance were significantly correlated with lower quality of life. Ethnic differences in the relationship between distress and mood disturbance with global quality of life and subscales of quality of life were observed. Actigraphic measures showed that in comparison with non-Hispanic patients, African Americans had significantly poorer activity/sleep (wake after sleep onset, 24-hour autocorrelation coefficient). Circadian disruption and inflammation were not associated with quality of life. Physiological dysregulation and associated comorbidities may take time to develop over the course of disease and treatment.