N Non-neoplastic proliferative lesions in the oral cavity such as gingival and pulp polyps have clinical manifestations as hypertrophic tissue and inflammatory reaction that mean an increase on the size of tissue and the number of cells within epithelial and subepithelial areas. Proliferation of epithelial cells can be examined immunohistochemically with a marker. One of them is Ki-67. Ki-67 protein expression can be used to observe the cause of cell proliferation at the gene level. The aim of this study was to determine the differences of Ki-67 protein expression on gingival and pulp polyps epithelium. Observational study was conducted using samples excision that have been diagnosed as gingival polyps (n=3) and pulp polyps (n=3). Samples were tested by immunohistochemistry for Ki-67 protein expression with monoclonal antibody Ki-67. The Ki-67 labelling index was determined by enumerating the percentage of Ki-67 positive cells to the total number of epithelial cells in the observed area at 10x10 magnification. T-test was used to analyze the differences of Ki-67 positive protein expression mean values on gingival and pulp polyps. The results showed that Ki-67 protein expression of gingival polyps (4.76±0.85)% was higher than pulp polyps (1.22±0.73)%. T-test analysis showed significant differences between the mean values of Ki-67 positive protein expression on gingival and pulp polyps (p<0.05).