Background The global cost associated with substitute treatment for patients with chronic kidney disease has been calculated, but there is a lack of information about the characteristics and costs deriving from pre-hospital care with transport and admission to hospital emergency services. Therefore, the aim of this study was to identify the characteristics of urgent telephone requests to Emergency Medical Services for patients with chronic kidney disease in Catalonia, Spain, and make a cost estimation of prehospital care and admission to the emergency department, grouped by comorbidities. Methods Retrospective longitudinal observational study. Patients who required urgent prehospital care based on telephone triage were enrolled. Sociodemographic, clinical, and financial variables were collected. The data were gathered by means of a review of the clinical records in the Emergency Medical Services database. To explore the possible relation among the qualitative variables the χ² test was used, for the relation between a quantitative variable and dichotomy qualitative variable the student t test was used with prior testing of the normal deviation of quantitative variables, and the Mann-Whitney U test was then employed if they did not fulfil normality criteria. For all calculations an alpha error of p <0.05 was assumed.Results A total of 252 phone calls were analyzed. Some 98.4% of patients (n=248) were prioritized through phone triage and classified as very severely ill: resuscitation or emergencies. The most prevalent initial diagnoses were intense dyspnoea, accidental fall, abdominal pain, and disease decompensation; there were 11 cases of cardio-respiratory arrest (4.36%), half of which were associated with hypertensive heart disease (HHDT). The average cost of prehospital care was €480.06/patient (SD=256.74), but in patients with comorbidities this rose to €550.77 for HHD and €508.73 for diabetes mellitus (DM). No statistically significant differences were found between total cost/patient and comorbidity (p=0.361), or between the costliest comorbidities, HHD and DM (p=0.330). Conclusions Patients telephoned for help when they were in serious condition, in line with the levels established by telephone triage. The cost of prehospital care was high, and this increased in the presence of comorbidities.