OBJECTIVE : Oncoplastic breast conserving surgery (BCS) frequently induces asymmetry. Contralateral reduction mammoplasty (CRM) is therefore part of the oncoplastic approach. Our patients frequently declined CRM when offered as a second-stage procedure after the completion of adjuvant treatments. This qualitative interview study was conducted to explore the factors involved in patient decision-making about CRM. METHODS : From the prospective hospital database of patients who underwent oncoplastic BCS for stage I-III breast cancer since 2010, 25 patients were sampled using stratified purposeful sampling on age, preoperative cup size, and time elapsed since the completion of adjuvant treatments. Nine had undergone CRM. Individual face-to-face semi-structured interviews were conducted at the hospital or at patients' homes. The interviews were audio-recorded, transcribed verbatim, and analyzed thematically. Data saturation occurred after analysis of the fifth interview, although variability within the data kept expanding until the last interview was coded. RESULTS : Eighteen patients reported postoperative breast asymmetry. Breast symmetry was important to our patients and information provision about CRM had been adequate. The following factors motivated patients to choose CRM: perceivable asymmetry, satisfaction with the outcome of oncoplastic BCS, and the wish for breast reduction before cancer diagnosis. Patients weighed these considerations against their concerns about surgery risks and recovery time. Reluctance to have nonessential surgery to the unaffected breast was an important reason to decide against CRM. CONCLUSIONS : Breast asymmetry is often tolerated after oncoplastic BCS because of concerns about surgery risks and recovery time and reluctance to have nonessential surgery to the healthy breast.