Introduction: Capsular contracture complicates a significant percentage of cosmetic and reconstructive breast procedures. An understanding of the molecular basis of capsular contracture may offer new treatment alternatives. The purpose of this study is to define the temporal expression of early molecular markers during breast implant capsule formation. Methods: Saline implants were placed under the dorsal skin of Sprague Dawley rats. The implants and capsules were harvested at 3 day intervals for 3 weeks. The capsules were tested for bursting strength and analyzed by histology and microarray. Results: The capsules were thin on day 3 and became progressively thicker. Maximal bursting strength was at 9 days. Array analysis showed > 400 genes which had a > 2-fold change in expression. TGF-beta cytokines had decreased expression, whereas VEGF and FGF-2 showed increased expression by day 6. Conclusions: In our rat model, a capsule develops within one week and progressively thickens. Array analysis demonstrates the similarity between capsule formation and skin wound healing with scar formation. During capsule formation, genes associated with inflammation and wound healing are expressed. An improved understanding of the temporal expression of these genes during normal capsule formation will help us to develop therapeutic strategies to reduce capsular contracture.