OBJECTIVE: To define care pathways in terms of frequency, costs, and outcomes and to assess their cost-effectiveness. DESIGN: Population-based cost-effectiveness study. SETTING: Auvergne EP registry (France). PATIENT(S): Women (n = 1,664) registered between 1994 and 2003. INTERVENTION(S): Standard diagnosis and treatment of EP. MAIN OUTCOME MEASURE(S): Costs before, during, and after hospitalization were assessed from data concerning medical costs of examinations and treatments. One-year fertility was used for effectiveness assessment. We assessed cost-effectiveness for the healthcare system. RESULT(S): Diagnostic ultrasound (47% of scans were nondiagnostic) was essential for the use of methotrexate as a first-line treatment for subacute EP. Hospital and ambulatory care costs were similar for all surgical-care pathways (diagnostic or nondiagnostic ultrasound scan followed by conservative or radical laparoscopy). Hospital and ambulatory-care costs associated with methotrexate treatment were less than half those for surgical-care pathways. In subacute cases, conservative treatments, and methotrexate in particular, were associated with better fertility at similar or lower cost to salpingectomy for EP for reproductive failure. CONCLUSION(S): Conservative treatments are cost-effective with respect to salpingectomy, when subsequent fertility is at stake. Efforts should be made to increase the frequency of diagnostic ultrasound scans, making it possible to increase methotrexate use and cost-effectiveness.