Retrospective analysis of ectopic pregnancies occurring in the past 36 mo. at the Beth Israel Hospital [Boston, Massachusetts, USA] yielded 2 [human] cases of concomitant intrauterine and extrauterine gestation. The incidence of coexistent intrauterine and ectopic pregnancy in this sample is 1/6778, or 0.015% of all pregnancies. These cases and 2 additional cases from another institution (Leonard Morse Hospital [Natick, Massachusetts, USA]) are reported on. Simultaneous intrauterine and ectopic pregnancy may be more common than previous statistics indicate.