We describe an experimental surgical model in early rabbit embryo (12.5 days of gestation). Twenty-one embryos were operated, of which 9 survived the first postoperative week and 5 had normal further growth until term. As far as we can ascertain, this is the first successful report of a surgical approach in early mammalian embryos. We think that this model may be useful for workers involved in the study of early congenital malformations.