In a review of the world's literature on combined intrauterine and extrauterine pregnancies, 589 cases, including five cases currently reported from the Sloane Hospital for Women, were documented. Analysis of the literature revealed abdominal pain to be the most frequent presenting symptom. A combination of signs and symptoms, including abdominal pain, adnexal mass, peritoneal irritation, and an enlarged uterus, was the most significant finding in support of a presumptive diagnosis of combined gestations. At the Sloane Hospital for Women, the occurrence of both pelvic inflammatory disease and combined pregnancy is approximately three times the reported world incidence. This proportionate increase in both disease states may support a potential etiologic association between pelvic inflammatory disease and simultaneous intrauterine and extrauterine gestations.