BACKGROUND The evaluation of a cancer patient can be affected by many factors. Cancer patients often have other diseases or medical conditions in addition to their cancer. These conditions are referred to as comorbidities. They can influence the treatment option, the rate of complications, the outcome, and can confound the survival analysis. OBJECTIVE It was the aim of this study to measure comorbidities in patients with laryngeal squamous cell carcinoma. METHODS Ninety adult patients treated for newly diagnosed laryngeal squamous cell carcinoma were studied. We measured comorbid illness applying the following validated scales: the Cumulative Illness Rating Scale (CIRS), the Kaplan-Feinstein Classification (KFC), the Charlson index, the Index of Coexistent Disease (ICED), the Adult Comorbidity Evaluation-27 (ACE-27), the Alcohol-Tobacco-Related Comorbidities Index (ATC), and the Washington University Head and Neck Comorbidity Index (WUHNCI). Survival analysis was performed using the Kaplan-Meier method (with the log-rank test value being used to compare groups). The Cox proportional hazards model was chosen to identify independent prognostic factors. RESULTS The mean age was 62.3 years. The majority of patients (36.7%) had early tumors. Forty patients were treated by surgery only, while the remaining 49 patients also received postoperative radiation therapy. Only 5 patients (5.6%) were lost to follow-up. Median follow-up time was 42.5 months. The 4-year overall survival was 63%. There was a statistically significant difference between survival rates according to clinical stage (CS I 87.3%, CS II 48.9%, CS III 74.7%, CS IV 23.9%; p < 0.001). Patients treated by surgery only presented a better survival rate (79.6%) than those receiving postoperative radiation therapy (48.9%; p = 0.001). A statistically significant difference in survival rates was also noted when patients were analyzed according to the type of surgical procedure. In a univariate analysis, comorbidity had impact on prognosis, no matter which scale was utilized: CIRS (p = 0.008), ACE-27 (p = 0.010), ATC (p = 0.004), WUHNCI (p = 0.003), Charlson index (p = 0.020), KFC (p = 0.001), and ICED (p = 0.010). However, in the multivariate analysis, only CIRS and TNM staging were identified as independent prognostic factors. CONCLUSIONS The comorbidity is an independent prognostic factor in patients with surgically treated laryngeal cancer. In the univariate analysis, all indexes were able to stratify patients. However, in the multiple analysis, only the CIRS was predictive of death. Comorbidities are an important factor in the analysis of overall survival.