Objectives: The aim of this study was to compare among PCNAand Ki-67 as the most reliable immunohisto chemical marker for evaluating cell proliferation in ameloblastic tumors. Study Design: Observational, retrospective, and descriptive study of a large series of ameloblastic tumors, com- D esign: Observational, retrospective, and descriptive study of a large series of ameloblastic tumors, com- esign: Observational, retrospective, and descriptive study of a large series of ameloblastic tumors, com posed of 161 ameloblastomas and four ameloblastic carcinomas, to determine and compare PCNA and Ki-67 expression using immunohistochemistry techniques. Results: When analyzing Ki-67 positivity, the desmoplastic ameloblastoma demonstrated a significantly lower proliferation rate (1.9%) compared with the solid/multicystic and unicystic ameloblastomas and ameloblastic car cinomas (p