Laryngeal dysplasia has a propensity to change into malignancy, the generally reported rate of this being about 14%. In this retrospective study of 125 patients, the authors have assessed the severity of dysplasia in relation to the incidence and time taken for malignant change. Out of 119 patients with laryngeal dysplasia, 21.8% turned malignant, 40.1% within a year and 71.9% within five years. The mean length of time for transformation to malignancy was statistically significant when comparing mild, moderate and severe dysplasia, this being 101, 52 and 28 months respectively. Analysis combining severe and moderate dysplasia as high grade and mild dysplasia as low grade also showed statistically significant differences in the time taken for transformation. The authors prefer this two-tier system. Coexisting epithelial dysplasia was reported in 74% of SCC reports, suggesting that biopsies can miss areas of SCC. The study reports a difference from previous publications which did not consider that severity of dysplasia is directly related to malignant transformation, and emphasises the significance of ‘moderate dysplasia’ in which 24% progressed to malignancy. Various treatment modalities and outcomes are discussed. The study also calls for a low threshold for repeat biopsies in the first year.