Objective: In this study, we aimed to present the demographic, ultrasonographic, genetic, obstetric, and postpartum results of 13 patients diagnosed with radial ray defects. Materials and methods: Thirteen patients diagnosed with radial ray defect between 2012 and 2024 were included in the study. Non-development or hypoplasia of any preaxial part of the upper extremity (radius, scaphoid, trapezoid bone, and thumb) on ultrasonography was considered a radial ray defect. Maternal age, gestational week at diagnosis, laterality of the radial ray defect, genetic results, presence of comorbid anomalies, termination status, and postpartum prognosis were obtained from the hospital records. Results: The range of maternal age at the time of diagnosis was 17-38 years and the gestational age ranged between 14-26 weeks. In the evaluation, four of the radial ray defects were bilateral, and nine were unilateral. Trisomy 18 was identified in two cases. Eight cases accepted the termination procedure. Two cases rejected termination and had spontaneous intrauterine death during pregnancy follow-up. One case was diagnosed with VACTERL association and died on postpartum 13th day. One case was monitored due to Fanconi aplastic anemia and one case had amniotic band syndrome in etiology and lives with a prosthetic arm. Conclusions: The frequency of radial ray defect accompanied by syndromic and congenital anomalies was high, and visualization of the radial bone or other preaxial bone structures on first-trimester fetal ultrasonography will ensure the diagnosis of radial ray defect in early gestational weeks. In case of a radial ray defect diagnosis, systemic organ screening should be performed with detailed ultrasonography and the necessary invasive procedure for karyotype examination should be advised to all families.