Ultrasonography was used in the second pregnancy trimester as a noninvasive method of prenatal diagnosis of congenital malformations (CM) in 1071 pregnant women. These were found in 1.2% of the examinees, were local and multiple with predominance of CNS anomalies. Key ultrasonic signs of CM are specified. It was noted that a fertilized egg presents valuable specific and nonspecific information. Ultrasonography is shown to be of high informative value in prenatal diagnosis of CM in the second trimester.