OBJECTIVES: Data concerning costs of illness in patients with schizophrenia are scarce in Germany. Aim of this claims data analysis was to examine the costs of schizophrenia from the perspective of a major statutory health insurance fund. METHODS: A nation-wide database was used to evaluate the costs of schizophrenia in 2006. All patients with schizophrenia (ICD F20) were identified via a special algorithm based on claims data. All schizophrenia related costs for outpatient care, inpatient care, medications, rehabilitation, occupational therapy, and sick leave payments were analysed. RESULTS: Data from 11,513 patients were available, with 47% being female (and 46 years of age). Mean costs of EUR 4,966 in the year 2006 were incurred from the health insurance perspective. A total of €2924 (59 %) were incurred by inpatient care, and €1333 (27 %) were due to medication. A total of €421 (8 %) resulted from schizophrenia related outpatient psychological specialists visits. Costs for rehabilitation were €27 (≤1 %), for occupational therapy €14 (≤1 %). Costs for sick leave payments came to €247 (5%) in 2006. Costs increase when a patient had an inpatient episode. A patient with at least one inpatient visit causes average annual costs of €15,487 (inpatient: €12,938; medication: €1552; outpatient: €322; rehabilitation: €108; occupational therapy: €16; sick leave payments: €551). A total of 2602 (23 %) patients had at least one inpatient visit in 2006. CONCLUSIONS: The major cost driver in schizophrenia from a health insurance perspective in Germany is inpatient care as well as to a lesser extent medication costs. Patients with at least one inpatient episode cause threefold cost compared with the average cost of schizophrenia.