BACKGROUND: Implant-based reconstruction is the most common procedure for breast reconstruction after mastectomy. Acellular dermal matrix is used to provide additional coverage in subpectoral and prepectoral implant placement. In this study, the authors compared postoperative outcomes between AlloDerm (LifeCell, Branchburg, N.J.) and DermACELL (Stryker, Kalamazoo, Mich.), two acellular dermal matrix brands. METHODS: A retrospective review of implant-based breast reconstruction from 2016 to 2020 was conducted. Patient demographics and comorbidities, implant size and location, acellular dermal matrix choice, and postoperative outcomes were recorded. Primary outcomes assessed were seroma and infection compared between two acellular dermal matrix brands. Independent clinical parameters were assessed with multiple logistic regression models for the primary outcomes. RESULTS: Reconstruction was performed in 150 patients (241 breasts). Eighty-eight patients underwent expander placement with AlloDerm and 62 patients with DermACELL. There were no significant differences in patient characteristics between the two groups. There was a significantly higher incidence of seroma in the AlloDerm group in univariate (AlloDerm 21.7 percent versus DermACELL 8.2 percent, p < 0.005) and multivariate analyses ( p = 0.04; 95 percent CI, 1.02 to 6.07). Acellular dermal matrix use (regardless of type) was not associated with higher rates of infection ( p = 0.99), but body mass index was ( p = 0.004). CONCLUSIONS: Both AlloDerm and DermACELL had similar infection rates regardless of contributing risk factors. AlloDerm was found to be a risk factor for seroma formation in the postoperative period. As such, it is important to be aware of this complication when performing implant-based reconstruction with this brand of acellular dermal matrix. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.