Introduction: Isotretinoin, a synthetic derivative of vitamin A, is one of the most potent human teratogens, and is mainly utilized for the treatment of severe recalcitrant nodular acne. Retinoic acid embryopathy is well defined in the literature. Case Report: The mother was referred for a fetal posterior fossa abnormality, first detected at 20 weeks of gestation. The mother used isotretinoin until 18 weeks gestation. Ultrasound examination revealed hypertelorism, cerebellar hypoplasia, vermian agenesis, truncus arteriosus, anotia, thymic aplasia, corpus callosum hypoplasia. An intrauterine diagnosis of fetal retinoid syndrome was confirmed by fetopsy after termination of pregnancy. Conclusion: The typical findings of fetal retinoid syndrome can be visualized with ultrasound in early second trimester.