Mucoepidermoid carcinoma (MEC) is a malignant glandular epithelial neoplasm having an unpredictable behavior and a tendency to recur. Numerous parameters have been assessed to predict the outcome of this lesion, but have been deemed inadequate, with the exception of tumor stage and grade. In the present study, we attempted to correlate the proliferative activity of MEC with its histopathological grade, using argyrophillic nuclear organizer region (AgNOR) count. Thirty cases of MEC were included in the study. All the slides were stained using hematoxylin and eosin and silver nitrate techniques. Counting was performed at a magnification of ×1,000 with an oil-immersion lens. Positive correlations were seen between AgNOR count and MEC grade (P < 0.05), with AgNOR count increasing in proportion with tumor grade. The AgNOR count in various grades of MEC indicates a relative progression in the proliferative activity of this tumor. This index is positively correlated with tumor grade, although there are some exceptions. The utility of AgNOR count in predicting the prognosis of MEC can be considered of importance; however, further assessment, such as survival studies, is necessary. (J Oral Sci 52, 275-279, 2010)