SUMMARY OBJECTIVE Evaluate the expression of KI-67 in uterine leiomyomas and adjacent myometrial tissue and verify the existence of a correlation between clinical parameters and KI-67 expression in tumors. METHODS This is a cross-sectional, controlled, analytical study. Samples of leiomyomas and myometrium were obtained from patients who underwent hysterectomy. The samples were processed by immunohistochemistry using KI-67 antibody, and the expression was evaluated by two blinded observers. Student›s T-test was used for comparison of means, and Pearson›s P test for correlation with clinical parameters. RESULTS A total of 9 patients were included in the study. The mean age was 40.7 years, ranging from 35 to 44 years. The mean expression of KI-67 in myometrium was 1.63%, and, in leiomyomas, 5.96% (p <0.001). The highest expression of KI-67 was moderately related to the severity of anemia, bleeding, and pain level. CONCLUSION The expression of KI-67 in normal myometrium was significantly lower than in leiomyomas. The highest expression of KI-67 was moderately related to the severity of anemia, bleeding, and pain level in the patients of this study.