Conclusion. Our results showed that the behavior of moderate dysplasia lesions was more like that of severe dysplasia lesions, while severe dysplasia was very different from carcinoma in situ (CIS). CIS should be managed more aggressively than the other lesions. Mild dysplasia could not be viewed as a precancerous lesion of the larynx. Objective: This study aimed to identify the possibilities of the precancerous lesions of larynx (including mild dysplasia, moderate dysplasia, severe dysplasia, and CIS) progressing to invasive carcinomas and to highlight the importance of adequate management and follow-up strategies for these patients. Methods: A retrospective study of patients who had these preinvasive lesions in the larynx over a 10-year period was performed. Results: These patients were followed for a minimum period of 2 years from the initial diagnosis. In all, 86 patients were identified the cohort. Of these, 17 (19.8%) patients developed carcinoma: 0 of 22 with mild dysplasia, 5 of 25 (20%) with moderate dysplasia, 2 of 14 (15%) with severe dysplasia, and 10 of 25 (40%) patients with CIS progressed to invasive cancers (p = 0.001). Over 50% of cases progressed 3 years after the original biopsy. Only 1 of 86 (1%) died of the disease.