The aim of study was to investigate the expression of the proliferation factor Ki-67 and its relationship with histological grade, cancer stage, and treatment outcome in squamous cell carcinoma of the larynx. Samples from 78 patients with laryngeal cancer were analysed retrospectively. Paraffin sections of tumors were immunohistochemically stained for Ki-67 expression. The patients were divided in two groups according to the proliferative factor values (a low Ki-67 index group - Ki-67≤34 and high Ki-67 index group-Ki-67 >34). Statistical analysis of the data shows significant correlation among histological tumor grade and the value of the Ki-67 proliferative index. There was no correlation between tumoral Ki-67 expression and diagnosis, stage of the disease, or treatment outcome. In conclusion, Ki-67 expression in laryngeal cancer is not the most reliable marker for making precise diagnosis and predicting the clinical course.