OBJECTIVES: In Brazil, law regulates the use of human albumin and divide recommendations into formal, questionable and unsubstantiated. The aim was to verify compliance with the requirements of this medicine in relation to national guidelines and calculate the costs of unsubstantiated indications of human albumin 20%, at a public hospital. METHODS: We evaluated the records of patients who used human albumin 20% during hospitalization at a public hospital in the period from August, 2013 to August, 2014. There were no restrictions as patient age or duration of therapy. Quantitative variables were expressed as by mean and standard deviation, and not quantitative variables in by absolute and relative frequency. RESULTS: We evaluated the records of 63 patients with a mean age of 60.6 ± 71.8 years. Most of them were men (40; 64.5%). Length of stay was 30.0 ± 47.2 days. Duration of albumin therapy was 6.0 ± 6.7 days (mean). Average total cost was US $ 174.13 ± 195.10 per patient. Nineteen (30.2%) of albumin indication was classified as questionable and 15 (23.8%) as unsubstantiated. Cost of unsubstantiated indications was US $ 2,379.80/year or US $ 158.65/patient, this represents 21.7% costs of albumin during the study period. Unsubstantiated indications were: use in intensive care (12; 19.0%), fluid replacement in acute losses (2; 3.2%) and hypoalbuminemia in patients with nephrotic syndrome (1; 1.6%). CONCLUSIONS: Of the total of prescriptions, 76.1% were compliance with indications in national guidelines. However, unsubstantiated prescriptions represented a cost of around 22.0% of the total budget spent on the acquisition of albumin and that could have been applied in other unmet needs due to lack of financial resources.