To choose the best possible dialysis technique for those patients with end-stage renal disease continues to be a matter of debate. Even after putting aside the evident influence that economic and geographic factors as well as the health politics may have in the selection of the technique, different studies comparing survival between hemodialysis (HD) and peritoneal dialysis (PD) have shown contradictory results which could be explained by the differing methodological and statistical methods used together with the different influence assigned to the comorbidity found when starting the treatment, a situation that has increased the confusion about this topic. Based on this we performed a retrospective analysis with a follow-up time of seven years including all those patients who started dialytic treatment in our area, with a final number of 3.106 hemodialysis patients and 542 peritoneal dialysis patients. Those patients who were transferred to another treatment technique during the time of the study were excluded. Age higher than 70 years, cardiovascular disease, liver disease, diabetes mellitus and the presence of dyslipidemia were included as comorbidity factors. Peritoneal dialysis patients were younger than those treated by hemodialysis (54.53 vs 60.1 years), but suffered from higher cardiovascular comorbidity and were more often diabetic. The global survival was the same in both groups up to 32 months of treatment. Although no differences were found when comparing those patients without comorbidity factors, those with comorbidity had better survival on hemodialysis. Age higher than 70 years was the only comorbidity factor with statistically significant difference for a better survival in hemodialysis.