Abstract Background The Swedish Breast Reconstruction Outcome Study (SweBRO) initiative is a nationwide study with the primary aim of assessing long-term outcomes after mastectomy with and without breast reconstruction (BR). The current part (SweBRO 2) is designed to evaluate health-related quality of life (HRQoL), with the hypothesis that BR has a positive impact on patient-reported HRQoL in the long-term. Methods Women who underwent mastectomy in Sweden in 2000, 2005, or 2010 and were alive at the time of the survey were identified through the National Breast Cancer Registry. Eligible participants received formal invitation letters to take part in a survey evaluating their HRQoL at 5 , 10, or 15 years post-mastectomy. The EORTC QLQ-C30, EORTC QLQ-BR23, and EQ-5D-3L questionnaires were employed. Results Of 2904 respondents (50% of 5853 invited), 895 (31%) had received BR. Among them, 516 (58%) were reconstructed with implants and 281 (31%) with autologous tissue. Women with BR scored significantly better in the EORCT QLQ-C30 physical functioning domain (mean 90 versus 81 points), fatigue (mean 21 versus 25), and dyspnoea (mean 16 versus 22) compared to non-reconstructed women. The EORTC QLQ-BR23 revealed that women with BR experienced favourable sexual functioning compared with non-reconstructed women (mean 26 versus 14). The EQ-5D-3L visual analogue scale score was similar between groups. Conclusion The current study underscores the benefits of BR for long-term well-being, for example, in terms of physical and sexual functioning. These underline the importance of informing women undergoing mastectomy about BR alternatives and its potential benefits in enhancing long-term well-being. The Swedish Breast Reconstruction Outcome Study (SweBRO) initiative is a nationwide study with the primary aim of assessing long-term outcomes after mastectomy with and without breast reconstruction (BR). Women who had undergone mastectomy in Sweden in 2000, 2005, or 2010 and were alive at the time of the survey were identified through the National Breast Cancer Registry. The current study underscores the benefits of BR for long-term well-being, for example, in terms of physical and sexual functioning.