The incidence of ectopic pregnancy has been increasing for many years and currently is two to three times higher than it was 20 or 25 years ago. The reasons for this are complex and include increased rates of pelvic and tubal infection, the use of the IUD, surgery in the pelvis for infertility, sterilization and other surgical procedures, in vitro fertilization, and improved diagnosis. Normal tubal physiology, the findings in affected tubes, and the mechanisms of how the ectopic pregnancy develops and involves the tube are considered. The cardinal points of the history and physical examination are presented in considerable detail. Further, the evolution of the tools of diagnosis--curettage, culdocentesis, laparotomy, laparoscopy, hormonal tests, and ultrasound-is considered. The different approaches to therapy are presented. Salpingectomy was once the method of accepted therapy, but currently conservative management (salpingostomy) is the most acceptable approach. More recently, selected patients are being treated with observation and a small subgroup are being managed with methotrexate and other chemical agents injected directly into the ectopic pregnancy. Ectopic pregnancy is still a leading cause of maternal death despite improved diagnosis and therapy. It should be remembered, however, that the total number of women who die from this condition is less than ever before and this is despite the rising incidence of ectopic pregnancy. There is still much to be learned about ectopic pregnancy, its etiology, diagnosis, and management.