Forty-five examples of epithelial odontogenic lesions (9 ameloblastomas (AB): 13 odontogenic keratocysts (OKC): 15 dentigerous cysts (DC): 6 radicular cysts (RC): and 2 odontogenic carcinomas (OC)) were immunohistochemically analyzed for the presence of p53 protein (p53P) and proliferative activity as indicated by positivity for Ki-67 antigen. p53P+ cells, detected as dense and/or faint nuclear staining, were found in 42 of the 45 odontogenic lesions examined.