Objective: To estimate the net cost of adding nicorandil to usual treatment for patients with angina and to compare this with indicators of health benefit. Design: Cost effectiveness analysis Setting: Based on results of the IONA (impact of nicorandil on angina) trial. Patients: Patients with angina fulfilling the entry criteria for the IONA trial Interventions: In one arm of the trial nicorandil was added to existing antianginal treatment and compared with existing treatment alone. Main outcome measures: Costs were for use of hospital resources (for cardiovascular, cerebrovascular, and gastrointestinal reasons), nicorandil, and care after hospital discharge. Benefits were assessed in three ways: (1) IONA trial primary outcome (coronary heart disease (CHD) death, non-fatal myocardial infarction, or hospital admission for cardiac chest pain); (2) acute coronary syndrome (CHD death, non-fatal myocardial infarction, or unstable angina); and (3) event-free survivors at the end of the trial. Results: The net cost for each additional IONA trial end point averted was -£5 (-€7). The net cost for each case of acute coronary syndrome averted was -£8 (-€12). The net cost for each event-free survivor was -£5 (-€7). These figures are based on gastrointestinal events that were judged definitely or probably related to nicorandil. When all gastrointestinal events were included these three ratios rose to £567 (€835), £886 (€1305), and £516 (€760), respectively. Conclusions: A substantial amount of the additional cost of nicorandil is offset by reduced use of hospital services. The limited comparisons possible with other CHD interventions suggest that nicorandil compares favourably.