BACKGROUND: Breast cancer is a disease that requires multimodality treatment, and surgical resection of the tumor is a critical component of curative intent treatment. Obesity, defined as a body mass index (BMI) > 30, has been associated with increased surgical complications. Additionally, sarcopenia, a condition of gradual loss of muscle mass, has been associated with worse breast cancer treatment outcomes. Sarcopenia occurs with increased age, inactivity, and poor diet leading to patient frailty, which can increase medical treatment complications. Even patients with high BMI can have sarcopenia (termed sarcopenic obesity). We investigated the association of sarcopenia with surgical complications for breast cancer. METHODS: A retrospective review was performed of patients diagnosed with breast cancer who received bioelectrical impedance spectrometry analysis of skeletal muscle mass and had surgery at our institution. Patient characteristics, treatment data, surgical type and complications were obtained from medical records. Multivariate logistic regression models were used to associate sarcopenia status and BMI with surgical complications, adjusted for other patient characteristics. RESULTS: We analyzed 682 patients with stage I to III breast cancer. On multivariable logistic regression controlling for age, BMI, comorbidities, and types of surgeries (lumpectomy, mastectomy with or without reconstruction), sarcopenia (p = 0.66) was not associated with surgical complications. Obesity was associated with a higher rate of surgical complications in patients who received mastectomy with reconstruction (p = 0.01). More complex surgical approaches were associated with a higher risk of surgical complications in our series. CONCLUSION: Compared with those undergoing lumpectomy or mastectomy without reconstruction, patients undergoing mastectomy with reconstruction were more likely to experience postoperative complications and obesity was associated with higher risk of complication in the latter group. We did not identify a correlation between sarcopenia and rate of adverse surgical outcomes.