OBJECTIVES: To analyse the health care utilization by patients diagnosed with major depressive disorder (MDD). METHODS: This was a retrospective longitudinal descriptive database study of the utilization of health care by patients with MDD from the South-West region of Sweden (1.5 million inhabitants). All patients who were diagnosed with MDD (ICD-10 F32 or F33) during 2007 were included in the study. All costs from healthcare visits when an MDD was the primary diagnose were included as well as all cost from all dispensed antidepressant (ATC N06A) drugs. RESULTS: A total of 37,445 patients had at least one health care visit with an MDD diagnoses during 2007 in the South-West region of Sweden. Sixty-two percent of the patients had at least one visit to the primary care, 35% had been treated as out-patient, 9% had been treated by private physician, and 7% had been treated by in-patient care; 73% had at least one dispensed drug. The total health care cost, including drug cost, was 683 million SEK. 35% were from drugs and 23%, 26%, 14%, and 1% were from in-patient, out-patient, primary, and private care. During 2007 the average drug cost per patient, who utilize the current treatment, was 8847 SEK for drugs. The average cost for in-patient care was 64,576 SEK and 13,859 SEK for out-patient care. For primary and private care the average cost was 4268 SEK and 1342 SEK. CONCLUSIONS: The cost for antidepressant drugs was the largest part of the total health care cost for MDD, 35%. The in-patient care was the greatest cost per patient. The relevant question is what mix of drugs should be prescribed in order to minimize the total health care cost. Further research needs to be preformed.