The medical and surgical treatment of gastroschisis has improved in the last decades leading to better survival rates. Since in our institution there were the same cyclic variations in the incidence as in other large series in the literature, we have reviewed the epidemiological factors that can be at the origin of such variations. We studied 20 different variables in our patients in a case-control basis. Only five of them were significantly different between cases and controls. (Birth weight, gestational age, infection, drugs during the first three months of gestation and maternal age). The results point to the role of environmental factors more relevant in the etiology of gastroschisis than genetic ones.