Introduction: The elderly population in Iran is growing, and more medical comorbidities can be identified, so hospital admissions of burn patients with associated medical comorbidities are expected to rise as well. As these medical comorbidities may affect the prognosis of burn patients, additional health care services are likely to be required. Therefore, the aim of this study was to determine the prevalence of comorbidities among patients with burn injury. Methods: A retrospective study of all burn patients admitted to the Motahari Burn Hospital, Iran over a 14-month period was conducted. Variables gathered from patients' medical record files were demographic characteristics, clinical burn features, hospital course, and preexisting comorbidities. The comorbidity score of patients was calculated by using the updated Charlson comorbidity index. Results: A total of 732 patients were hospitalized, 136 (18.5%) patients had comorbidities, and more than 57% of elderly people (!61 years) had one or more comorbid conditions. The most common cause of burn injury among the comorbid patients was scald (38.2%) injury. The two most frequent comorbid conditions among all cases were congestive heart failure (25.8%) and diabetes (23.5%), respectively. As patients got older, the Charlson score also increased. There were no significant differences between comorbid and noncomorbid patients in terms of hospitalization period and mortality rate. Those comorbid patients who died had significantly higher Charlson score and larger mean burn sizes compared to surviving comorbid patients; they were also significantly older. Conclusion: The prevalence of comorbidities in burn patients was 18.5% and among older burn patients rose to 57%. Diabetes and congestive heart failure were the two most common comorbid conditions.