The coincidence of gastric cancer and pregnancy is a rare event. By literature research of the last three decades only 31 cases from outside Japan were identified including two own patients. The analysis of these and another 61 cases from Japan revealed the same predominance of poorly differentiated diffuse carcinomas with peritoneal and lymphatic metastases as in other young patients (<40 years). The survival rate is not obviously affected by pregnancy, young age or female sex. Experimental and epidemiological data suggest a protective effect of oestrogen against the induction of (intestinal) gastric cancer, while the cancer growth itself seems to be enhanced. Oestrogen receptors (ER) are found in about 22% of gastric cancer cells, especially in the poorly differentiated type. In contrast to target organs like the breast, ER in gastric cancer seem to be a sign of tumour adaptation involving e.g. the pathway of the epidermal growth factor. The results of treatment with anti-oestrogen are controversial in experimental and clinical settings. Due to the very common epigastric complaints early diagnosis of gastric cancer is even more difficult in pregnancy, so that early gastroscopy is advisable in patients on risk. Main effort should be given, however, to primary prevention.