This study aimed to discover to what extent ethical issues are considered in the reimbursement decision process based on health technology assessment (HTA) in Korea, especially for oncology medications. Public summary documents (PSDs) published by the Health Insurance Review and Assessment Service (HIRA) were analyzed for empirical and normative factors. For external comparison, PSDs presented by corresponding institutions of Australia and the United Kingdom were employed. Furthermore, the opinions of eight expert oncologists were obtained regarding the accountability of the evidence in PSDs. Among 7 oncology drugs, there were differences in the final decisions and empirical factors considered, such as selected comparators and interpretation of evidence between the PSDs from the three institutions. From an ethical viewpoint, the following matters were deficient in the HTA decision-making process for oncology drugs: clear and reasonable standards; identifying and evaluating ethical values; and public accountability for reasonableness about decisions and due process.