OBJECTIVES: The aim of this study is to calculate the market share of drug cost from the total health insurance cost of treatment of breast, cervical and colorectal cancer. METHODS: Data derives from the central, nationwide database of the Hungarian National Health Insurance Fund Administration (OEP) covering the year 2001. The cost of treatment includes the cost of outpatient care, the acute and chronic inpatient care, the (subsidies) of medicines' prices (reimbursement) and the expenditure on disability to work. The subsidies of drugs include the following ATC codes: "L" (Antineoplastic and immunomodulating agents), "N02" (Analgesics) and "A04" (Antiemetics and antineuseants). The diseases were identified with the following ICD (International Classification of diseases): breast (C50, D05, D24), cervix (C53, D06, D26.0) colorectal (C18, C19, C20, C21, D01.0, D01.1, D01.2, D01.3, D01.4, D12). RESULTS: The total health insurance cost of treatment of breast cancer was around 33.4 € million (8.6 billion Hungarian forint) in 2001. The total health insurance cost of treatment of cervical cancer was around 4.1 € million (1 billion Hungarian forint) in 2001. The total health insurance cost of treatment of colorectal cancer was around €38,871,666 (9.98 billion Hungarian forints) in 2001. The drug cost of breast cancer was 9.45 million EUR, cervical cancer 0,62 million EUR and colorectal cancer was 4.86 € million. The market share of drug reimbursement cost from the total health insurance cost was the following: breast cancer (28.3%), cervical cancer (15.4%), colorectal cancer (12.5%). CONCLUSIONS: The health insurance reimbursement of drugs varies in different types of cancer. The drug costs represent the highest cost element in breast cancer compared to cervical and colorectal cancer.