Gastric cancer associated with pregnancy is quite rare, and is most often diagnosed at an advanced stage. Furthermore, physicians are confronted with two conflicting issues in this condition: the need for early treatment of the maternal gastric cancer and the continuation of the pregnancy. To clarify the characteristics of pregnancy-associated gastric cancer and to obtain useful information that would help us choose the best treatment strategy for pregnancy-associated gastric cancer, we reviewed the existing literature, using the key words "pregnancy" and "gastric cancer". We were able to accumulate 136 cases, including 100 cases reported previously in Japan, and 1 case that we report here. We analyzed a total of 137 cases in the present study. With respect to the stage of gastric cancer, 92.5% of the patients studied had advanced gastric cancer, and only 45.3% of the patients underwent gastrectomy, including incomplete resection. Accordingly, the prognosis was very poor; the 1- and 2-year survival rates were 18.0% and 15.1%, respectively. However, the number of patients found to have early gastric cancer by endoscopic examination has been increasing recently. An endoscopic examination should be conducted immediately in pregnant patients presenting with persistent gastrointestinal symptoms for the differential diagnosis of hyperemesis gravidarum. When an endoscopic examination reveals that pregnant patients have gastric cancer, a therapeutic plan should be promptly formulated, in accordance with the number of weeks of gestation, by a medical team consisting of specialists in perinatal obstetrics and gastric cancer specialists.