Aim: 24 cases of single umbilical artery (SUA) are presented and the related histopathological findings of the fetuses and placentas examined. SUA is the most common congenital anomaly of the umbilical cord, resulting in the absence of one of the two umbilical arteries. It has an incidence of approximately 2.1% in autopsy material and there is evidence that is associated with anomalies of the fetus and placenta. Material-Method: The files were reviewed of 24 cases with SUA, out of 1,570 autopsies of fetuses and placentas performed in the Pathology Laboratory of Aretaieion Hospital, due to spontaneous or induced abortions after written parental consent. Results: The incidence of SUA was 1.6%. Gestational age ranged between the 15th and 33rd week and mother’s age ranged from 17-44 years. Three of 24 cases were twin pregnancies; 17/24 fetuses were male. In 21/24 cases complex congenital anomalies were observed and in five of 24 cases chromosomal anomalies were detected. In eight of 24 placentas extensive infarcts were observed; 7/24 dysmaturity, 5/24 severe chorioamnionitis, 3/24 extensive fibrin accumulation and 1/24 chorioangiosis. Conclusion: SUA is an umbilical congenital anomaly associated with severe fetal congenital anomalies and once detected with ultrasound techniques, further and more detailed control of the fetus is considered mandatory.