OBJECTIVE: To assess resources mobilized per day and per patient receiving palliative care (PC) and to explain the observed cost variability. STUDY SETTING: We conducted a prospective study in four French PC units. STUDY DESIGN/DATA COLLECTION: For each patient, socio-demographic and medical data were collected (using a case-report form developed specifically for this purpose) and a daily cost for the provision of care was estimated. Three methods were used to analyse causal relationships. The first method was to ask the PC staff, individually and in group meetings, their own perception of the relationship between daily costs and the other variables; the remaining two methods used the data collected in the prospective study: correlational analysis and segmentation. The database contained 140 hospitalization sequences. PRINCIPAL FINDINGS: The daily cost per patient was, on average, Euro 434 (standard deviation: Euro 73) and ranged from Euro 301 to Euro 667. Beyond differences in resources between PC units in this study, six variables were predictive of higher costs: degree of anxiety of patients and/or their families; proximity of death; extreme dependence; ENT cancer; relatively young age of the patient; and provision of certain procedures (drip, syringe driver, aspiration, oxygen therapy). CONCLUSIONS: These elements suggest using, not a single rate to finance this type of care, but modifying this tariff according to the characteristics of the patients. They raise the question about the criteria to be used if such a step were to be taken.