OBJECTIVES: The long-acting injectable aripiprazole once-monthly 400 mg (AOM 400) has been approved for treatment of schizophrenia in Finland since November 2013. Other atypical anti-psychotics, risperidone, paliperidone and olanzapine are also available as long-acting injectable formulations. A mixed treatment comparison has demonstrated that AOM 400 is at least as efficacious as other atypical long-acting anti-psychotics (ALAIs). However, cost of administration and drug (treatment cost) vary among the ALAIs. This analysis aims to investigate the total treatment costs of ALAIs using real-world data in Finland. METHODS: A one-year time horizon budget impact analysis was conducted to compare the treatment costs of ALAIs in Finland. The real-world doses were calculated using sales data. One of the ALAIs (olanzapine) can be given in intervals of 2 or 4 weeks using the 300 mg strength. Half of the patients were assumed treated with the 300 mg dose every 2 weeks, the other half every 4 weeks. Prices for ALAIs were obtained from the official national price list. The cost of administration for AOM 400, paliperidone-LAI and risperidone-LAI was based on the cost of a short nurse visit (30 minutes) to a psychiatry outpatient clinic. The cost of administration of olanzapine-LAI was based on the cost of a longer visit (120-180 minutes), as the product information recommends monitoring for three hours after injection. RESULTS: The expected cost for drug and administration per patient, per year, for AOM 400 is 5158 EUR. The expected yearly costs per patient for drug and administration for paliperidone-LAI, risperidone-LAI and olanzapine-LAI are 6021 EUR, 6706 EUR and 11646 EUR respectively. CONCLUSIONS: In a budget impact analysis, using the method, data and assumptions described, AOM 400 is expected to be cost saving, in the real-world setting, in terms of cost of drug and administration, compared to other ALAIs available in Finland.