BACKGROUND: The trend towards breast reconstruction post-mastectomy has increased, aiming to enhance patient outcomes and quality of life. This study examines the impact of immediate breast reconstruction (IBR) on survival outcomes compared to mastectomy alone (MA). MATERIALS AND METHODS: We conducted a retrospective cohort study of breast cancer patients aged 20-79 years with MA or IBR from 2010 to 2015. Propensity score matching (PSM) was utilized to balance the cohorts. Survival analysis assessed overall survival (OS) and breast cancer specific survival (BCSS), with subgroup analysis was performed. RESULTS: The median follow-up period was 93 months. After PSM, 16,220 female patients were matched. IBR was associated with improved OS (HR = 0.74, 95 % CI 0.69-0.79, p <
0.001) and BCSS (HR = 0.84, 95 % CI 0.78-0.91, p <
0.001). Patients who needed radiotherapy tended not to receive IBR. IBR achieved a survival advantage in OS across the subgroups including age, marital status, histology grade, T stage, N stage, chemotherapy status, and radiotherapy status. In patients aged 60-79 years, with Black ethnicity, with local median household income <
0,000, IBR's survival advantage is in OS but not BCSS and IBR was not inclined to be chosen among these groups. CONCLUSION: IBR's OS advantage over MA is universal in all stratified age groups, marital statuses, histology grades, T/N stages, and chemo/radiotherapy statuses. For patients aged 60-79 years, with Black ethnicity, with a local median household income <
0,000 and requiring radiotherapy, IBR is survival-beneficial but these groups tend not to receive it.