Aim: Hemodialysis and peritoneal dialysis are renal replacement treatment options in patients with chronic renal failure. Mortality and morbidity rates are higher in hemodialysis and peritoneal dialysis patients when compared to the healthy population. Comorbidities of the patients play roles in the high mortality and morbidity rates. In the present study, the comorbidities of hemodialysis and peritoneal dialysis patients were evaluated; and the Charlson Comorbidity Index, whose reliability was proven in many studies before, was compared and discussed. Materials and Method: A total of 154 patients (78 hemodialysis and 76 peritoneal dialysis patients), who were followed up for end-stage renal disease, were included in the study. The Charlson Comorbidity Index scores of the patients were calculated. The Charlson Comorbidity Index score and parameters were compared between patient groups on hemodialysis and peritoneal dialysis. Results: The Charlson Comorbidity Index was found to be significantly higher in peritoneal dialysis patients than in hemodialysis patients (p=0.001). It was also found that the frequency of congestive heart failure, cerebrovascular accident, and connective tissue, which are the parameters of the Charlson Comorbidity Index, were significantly different between the groups (p
