Acellular dermal matrices are used in a variety of reconstructive and cosmetic procedures. There seems to be host tissue integration, revascularization, and recellularization into these products, but the exact timing and differences among these remain unknown. The purpose of this study is to determine and compare these properties of 4 different acellular dermal matrices (AlloDerm, DermACELL, DermaMatrix, and Integra) in an in vivo rat model. Tissue specimens were obtained at various time points. Histology and immunohistologic assays were used to quantify the extent of cellular infiltration and revascularization within the various matrices. A bimodal cellular response was observed in all products except for DermACELL. Cellular infiltration was highest in DermACELL and lowest in AlloDerm, and angiogenesis was evident by day 7. There were clear differences within the various products. It is undetermined whether these differences are advantageous or clinically significant. Future work is needed to define the specific roles for each.