Objective: A needs assessment can be used as a direct index of what patients perceive they need help with. The purposes of this study were to investigate the association between patients' perceived needs and psychological distress and/or quality of life (QOL) and to clarify the characteristics of patients with a high degree of unmet needs.Methods: Randomly selected ambulatory female patients with breast cancer participated in this study. The patients were asked to complete the Short-form Supportive Care Needs Survey questionnaire, which covers five domains of need (health system and information, psychological, physical, care and support, and sexuality needs); the Hospital Anxiety and Depression Scale; and the European Organization for Research and Treatment of Cancer QLQ-C 30.Results: Complete data were available for 408 patients. The patients' needs were significantly associated with both psychological distress (r 5 0.63, po0.001) and QOL (r 5 À0.52, po0.001). A multiple regression analysis revealed that employment status (without full-time /part-time job), duration since diagnosis (less than 6 months), advanced stage, and a lower performance status were significantly associated with higher total needs. Only sexuality needs were significantly associated with a younger age, while the other domains were significantly associated with duration since diagnosis, advanced stage, and a lower performance status.Conclusions: Moderate to strong associations exist between patients' needs and psychological distress and/or QOL. The characteristics associated with patients' needs are multi-factorial, and interventions to respond to patients' needs may be one possible strategy for ameliorating psychological distress and enhancing QOL.