Objective: In order to elucidate the retrogressive degeneration of orofacial cleft, the fissured tissues of prenatal and postnatal cleft lip and palate were examined by histological and immunohistochemical methods. Design: Totally 42 cases of prenatal (n=17) and postnatal (n=25) cleft lip and/or palate were examined in comparison with 10 cases of normal lip and oral mucosa using immunohistochemical stainings of MMP-3, MMP-9, MMP-10, cathepsin G, PCNA, E-cadherin, TGase 2, HSP-70, vWF, and VEGF. Main Outcome Measures: In the fissured tissue the sebaceous glands were strongly positive for PCNA and grew into the underlying fibromuscular tissue (24/42). Some hyperplastic sebaceous glands of prenatal cleft lip produced infundibular follicular cyst (9/17). The skin and mucosal epithelia from the postnatal cleft lip and palate (10/25) showed severe basal hyperplasia (11/25) and melanocyte infiltration (7/25). Results: The immunostaining of MMP-3 and HSP-70 were strongly positive in the hyperplastic sebaceous glands and nearby atrophying muscle bundles of the fissured tissue, while MMP-9, MMP-10, and cathepsin G were almost negative. The immunoreactions of the other antibodies used in this study were similar between in the fissured tissues and in the normal controls. Conclusions: These data suggest that the over-expression of MMP-3 is closely related to the sebaceous gland hyperplasia, epithelial dysplasia, and the muscle degeneration, and that the over-expression of MMP-3 in the fissured tissue may continuously aggravate the cleft condition in the later life.