Tenascin-C (TN-C), an extracellular matrix glycoprotein, is known to be expressed in uterine stroma in the peri-implantation period. Examination of the spatiotemporal pattern during early pregnancy using immunohistochemistry and in situ hybridization revealed TN-C expression in the stroma beneath the luminal epithelia of the murine endometrium on Days 0 and 1 of pregnancy, subsequent disappearance, and reappearance on Day 4. After decidualization, tissue around the deciduoma was positive. In situ hybridization demonstrated TN-C production by the stromal cells adjacent to the epithelia. To investigate the regulation of TN-C expression in vitro, murine uterine stromal and epithelial cells were isolated and cultured. Addition of interleukin-1α (IL-1α) and prostaglandin E₂ (PGE₂) and F_2α (PGF_2α) induced TN-C expression in the stromal cells at both protein and mRNA levels, while the sex steroid hormones, progesterone and β-estradiol, exerted little effect. Immunohistochemistry using anti-IL-1α antibody showed epithelial cells to be positive on Days 2–4 of pregnancy, and addition of progesterone but not β-estradiol enhanced IL-1α expression in epithelial cells in vitro. In a culture insert system, TN-C expression by stromal cells cocultured with epithelial cells was induced by addition of progesterone alone that was blocked by additions of anti-IL-1α antibody. Collectively, these findings indicate that TN-C expression in the preimplantation period is under the control of progesterone, but not directly, possibly by the paracrine and autocrine intervention of IL-1α secreted by epithelial cells and PGE₂ and PGF_2α secreted by stromal cells.