In 2016, more than 40% of women who underwent mastectomy for breast cancer went on to have breast reconstruction, but there is little data regarding long-term cosmetic outcomes past 5 years after post-mastectomy radiation (PMRT) and reconstruction. This study aims to evaluate the difference in patient breast satisfaction and sexual well-being over time by receipt of reconstruction and PMRT. The iCanCare study is a population-based, longitudinal study of women diagnosed with breast cancer in 2014-15 identified in the Los Angeles and Georgia SEER registries. Women were surveyed during initial treatment and again approximately 6 years later in survivorship (2021-2022). Participants were asked about their "Sexual well-being after mastectomy" and "Satisfaction with breasts" using the Breast-Q, which was dichotomized into "high" and "low" scores (using the median), with a high score indicating increased satisfaction. We then evaluated whether satisfaction differed by treatment characteristics, using unadjusted odds ratios (OR) for categorical variables, calculated using the Chi-square test, or the Kruskal-Wallis test for continuous variables. Adjusted odds ratios were found using multivariable logistic regression models adjusting for treatment characteristics, diagnosis, age, BMI, education, and breast cancer stage. In this preliminary sample of 1191 respondents, 445 underwent mastectomy, of which 272 (61.12%) had reconstruction, and 65 (14.61%) had PMRT. Having breast reconstruction was associated with higher long-term sexual well-being (median score 36.30 vs. 22.20, OR 1.69, 95% confidence interval [CI] 1.09 - 2.64) and breast satisfaction scores (OR 1.53, 95% CI 1.01 - 2.33) compared to not having reconstruction. However, this improvement in sexual well-being was attenuated in women who additionally had PMRT (OR 0.83, CI 0.271 - 2.51). In women who did not have reconstruction after mastectomy, there was no statistically significant difference in sexual well-being scores regardless of the use of PMRT (OR 0.68, CI 0.39 - 1.22). Among respondents in adjusted models who did not receive PMRT, those with reconstruction had higher sexual well-being scores than those with without reconstruction (aOR 2.47, CI 1.34 - 4.56), though there was no statistically significant difference in breast satisfaction scores (p = 0.16) among the groups. Sexual well-being and breast satisfaction are improved with reconstruction 6 years after mastectomy for breast cancer. However, these improvements were attenuated for women who received PMRT. To our knowledge, this is the first study to look at long term outcomes of sexual well-being and treatment satisfaction after breast reconstruction for patients who underwent mastectomy for breast cancer. These data suggest that continued work should be done to optimize patient outcomes when combining PMRT and breast reconstruction.