BACKGROUND Premenopausal women represent approximately 35% of new breast cancer diagnoses. Diagnosis and treatment may lead to substantial disruption in quality of life (QOL). METHODS Premenopausal patients (aged 18 to 50 years) treated for nonmetastatic breast cancer completed a mailed questionnaire. Multiple self-reported QOL measures and clinical data were collected. Cluster analysis and Cronbach’s α were used to validate the survey. Analysis of variance was performed for specific interventions. Lower interference scores conveyed higher QOL. RESULTS The response rate was 49.8%. Cronbach’s α was 0.96. Immediate contralateral prophylactic mastectomy (CPM) carried the highest interference (mean, 3.3148) with sexuality compared with no CPM (mean, 2.85) or delayed CPM (P = .03). Breast conservation had the least interference with appearance (P < .01) and work and finances (P = .02). CONCLUSIONS Therapeutic mastectomy and CPM with or without reconstruction may adversely affect QOL. These findings suggest that the choice and timing of interventions may significantly affect patient satisfaction.