Ultrasonographic investigations in a family with two members (uncle and niece) with bilateral renal agenesis disclosed various urogenital malformations (pelvic kidney, unilateral renal agenesis, duplication of kidneys and exstrophy of the cloaca). Pedigree and types of malformations found, focused on renal adysplasia, a condition caused by an autosomal dominant gene with incomplete penetrance and a wide range of expression. Carriers of the gene may reveal variable urogenital malformations, including uni- or bilateral renal agenesis of dysplasia, horseshoe kidneys, pelvic kidney and others. Prenatal ultrasonographic diagnosis is essential in pregnancies of potential or established carriers of the gene. In the present family, 2 subsequent pregnancies were subjected to ultrasonographic diagnosis; in one, fetal renal agenesis was detected and confirmed in the subsequently aborted fetus. Fetal ultrasonography with special attention paid to urogenital anomalies is indicated in any pregnancy of an established or potential carrier of the gene for renal adysplasia.