BACKGROUND: Comorbidity has been shown to be a determinant in treatment selection and survival in various cancers. We have previously shown that the Adult Comorbidity Evaluation-27 index is applicable in a United Kingdom setting, and the process of comorbidity grading by retrospective notes evaluation is an accurate and reliable process. METHODS: The impact of comorbidity and other factors on survival was examined retrospectively in a cohort of 180 patients with laryngeal squamous cell cancer. RESULTS: This study shows for the first time that the higher comorbidity burden seen in supraglottic cancers in contrast to glottic tumors might account for the poorer prognosis. This study also externally validates the composite comorbidity-TNM staging system described by Piccirillo and shows the composite system to be a better predictor of outcome than TNM staging system alone. CONCLUSIONS: Moderate and severe comorbidity have a greater and statistically significant impact on survival than the TNM staging system.