In order to know the degenerating state of postnatal cleft lip tissue, total 23 cases of lip biopsy obtained from cleft lip surgery were collected and examined pathologically. The cleft lip tissues characteristically disclosed epithelial hyperplasia (13/23), stromal myxoid degeneration (20/23), salivary gland degeneration (1/23), muscular degeneration (11/23), and sebaceous gland hyperplasia (15/23), melanocytic infiltration (5/23). The epithelial hyperplasia was marked with hyperkeratosis and basal hyperplasia, which was usually coincident with the myxoid degeneration of underlying connective tissue. The myxoid degeneration was diffuse in the deep connective tissue with chronic inflammatoryreaction, and followed by extensive muscular degeneration. The sebaceous gland hyperplasia was usually predominant in the skin area of the cleft lip. In this study the lip biopsy from 30years old patient still showed remarkable retrogressive degeneration of lip tissue. Therefore, it is considered that the postnatal cleft lip tissue is continuously degenerative, and its retrogressive change gradually affects the deterioration of perioral muscular structures, consequently resulted in the failure of lip functions as well as further bizarre malformation of oro-facial shape during the postnatal period. These data also indicate that the biopsy of postnatal cleft lip should be recommended to know its variable degenerating status and to perform the proper rehabilitation surgery of cleft lip.