Objectives : The purposes of this study is to estimate the cost of cancer care after its diagnosis and to identify factors that can influence the cost of cancer care. Methods : The study subjects were patients with an initial diagnosis one of four selected tumors and had their first two-years of cancer care at a national cancer center. The data were obtained from medical records and patient surveys. We classified cancer care costs into medical and nonmedical costs, and each cost was analyzed for burden type, medical service, and cancer stage according to cancer types. Factors affecting cancer care costs for the initial phase included demographic variables, socioeconomic status and clinical variables. Results : Cancer care costs for the initial year following diagnosis were higher than the costs for the following successive year after diagnosis. Lung cancer (25,648,000 won) had higher costs than the other three cancer types. Of the total costs, patent burden was more than 50% and medical costs accounted for more than 60%. Inpatient costs accounted for more than 60% of the medical costs for stomach and liver cancer in the initial phase. Care for latestage cancer was more expensive than care for early-stage cancer. Nonmedical costs were estimated to be between 4,500,000 to 6,000,000 won with expenses for the caregiver being the highest. The factors affecting cancer care costs were treatment type and cancer stage. Conclusions : The cancer care costs after diagnosis are substantial and vary by cancer site, cancer stage and treatment type. It is useful for policy makers and researchers to identify tumor-specific medical and nonmedical costs. The effort to reduce cancer costs and early detection for cancer can reduce the burden to society and improve quality of life for the cancer patients.