The incidence of ectopic pregnancy has increased 4.5-fold in the United States since 1970. Several risk factors have contributed to this rate of increase, but the primary underlying cause remains undefined. Significant advances in the diagnosis of ectopic pregnancy have occurred during this same interval as a consequence of an enhanced understanding of the natural course of the disease. Characteristic changes in human chorionic gonadotropin levels, ultrasound findings, and more frequent use of laparoscopy have contributed to earlier, more consistent diagnosis. Advances in treatment, including tubal-conserving operations, laparoscopic approaches, and medical treatment with methotrexate, have all proved to be safe and effective. The remaining principal challenge is to improve future fertility, which is often adversely affected by recurrence of an ectopic pregnancy.