The purpose of the study to seek the differences of cell proliferation index among dentigerous cyst, dentigerous with ameloblastoma and ameloblastoma plexiform. This study utilized retrospective method, which was achieved by collecting data from medical record in oral surgery clinic, Cipto Mangunkusumo Hospital and Pathology Anatomy Laboratory at Faculty of Medicine University of Indonesia from Januari 1998 to April 2002. Histological examination were prepared from 34 samples; consist of 15 dentigerous cysts, 11 ameloblastoma and 8 dentigerous cyst which arise with ameloblastoma. In each case, intra-nuclear AgNOR dots were counted in 100 consecutive basal nuclei. Statistic analysis using ANOVA show the difference among study objects (p<0.05). AgNOR an ameloblastoma is significantly higher than in dentigerous cyst. The differences may indicate the variation of metabolic, proliferation or transcriptional activities of the cell. The study found the difference of AgNOR count in cell proliferation index among dentigerous cyst, dentigerous cyst which arise with ameloblastoma and ameloblastoma. The finding can be used to determine the diagnoses in doubtfull cases where dentigerous and ameloblastoma cannot be distinguished clinically and pathologically.