The aim of this study was to describe the prenatal detection of fetal nasal abnormalities by ultrasound. Transvaginal and transabdominal sonography was used for the detection of fetal malformations in 25, 114 cases. The fetal nose was visualized in all the fetuses in an oblique section and in the lateral profile of the face. Fifteen cases of fetal nasal malformations were detected between the 12th and 27th week of gestation. All but two, who had dilatation and curettage, were confirmed by postabortal or postnatal examination. Dyskaryosis (trisomies 18 and 21, triploidy, and tetrasomy 12 p) was diagnosed in six cases (40 per cent). The nasal malformations were isolated in four cases, one of them being associated with tetrasomy 12 p. The fetal nose should also be a target in the prenatal sonographic screening for malformations in the early mid-trimester. The incidence of fetal nasal anomalies is 1:1674 fetuses (15:25, 114). The fetal nose should be visualized by ultrasound in both an oblique plane and a lateral profile to identify its abnormalities.