Non-specific granulomas of the larynx may be caused by an inflammatory change in the posterior wall of the larynx, an occurrence which often happens after excessive vocal use, coughing, throat clearing, or tracheal intubation. We report a case of non-specific granuloma of the larynx, in which malignant transformation had occured 5 years and 3 months after initial treatment. Malignant transformation in non-specific granulomas is extremely rare, but it is important to examine the laryngeal lesion carefully, and to maintain a strict followup to avoid missing malignant transformation.