OBJECTIVE: To prove the origin of myoepithelial tumors using immunohistochemical analysis as well as to accurately differentiate benign from malignant tumors using the Ki-67 proliferative index and morphometric analysis of tumors' nuclei. STUDY DESIGN: The study included 18 myoepitheliomas, 12 myoepithelial carcinomas, and 16 pleomorphic adenomas. Nine antibodies were used for the immunohistochemical analysis. A digital morphometric analysis was performed on tissue sections of a salivary gland tumor using ImageJ. Eight variables were analyzed. The Ki-67 labeling index was calculated from the ratio of the positive number of tumor cells to the total number of tumor cells counted per microscopic field. RESULTS: The immunohistochemical analysis was essential in proving the origin of myoepithelial tumors. The value of the Ki-67 proliferative index is significantly higher in myoepithelial carcinomas as compared to myoepitheliomas (p < 0.001) and pleomorphic adenomas (p < 0.01). The following results were obtained using morphometric analysis. In the patients with myoepithelial carcinomas the values of nuclear size were significantly higher as compared to the patients with myoepitheliomas (p < 0.05). In comparison to pleomorphic adenoma, the parameter values of area, perimeter, Feret diameter, and minimum Feret were higher (p < 0.05), as well as the parameter value Integrated Optical Density (p < 0.01). Compared to the patients with pleomorphic adenomas, the patients with myoepitheliomas expressed significantly higher Integrated Optical Density parameter values (p < 0.05). CONCLUSION: We consider that it is necessary to do an antibody panel with the Ki-67 proliferative index calculation as well as to carry out the morphometric analysis of the nuclei of these cells. © Science Printers and Publishers, Inc.