Objective: The aim of this study was to explore reasons for delay in seeking medical help and nonadherence to treatment in Indonesian women with breast cancer. Method: Semistructured interviews were conducted by purposive sampling, using a consecutive sample of 50 breast cancer patients who were treated at the Outpatient Surgical Oncology Clinic of Hasan Sadikin Hospital in Bandung, Indonesia. Interviews were recorded, transcribed verbatim, and coded using qualitative software. Codes were merged into main themes that were subsequently mapped onto the study's aim. Results: Eight main themes concerning reasons for delay in seeking medical help and treatment nonadherence emerged, namely: lack of awareness and knowledge, cancer beliefs, treatment beliefs, financial problems, emotional burden, severe side effects, paternalistic style of communication, and unmet information needs. Conclusion: This study has identified several modifiable psychosocial and cultural factors related to delay in seeking help and nonadherence to treatment in breast cancer patients. We suggest that the provision of extensive information through media campaigns, treatment decision aids, and caregiver and patient education are needed to change the illness behaviors of Indonesian breast cancer patients. © 2013 American Psychological Association.