We present eight cases of suprarenal masses detected sonographically in fetuses of 20-41 weeks. The appearances of the masses included hyperechoic (n = 2, both pulmonary sequestrations), solid isoechoic (n = 1, a neuroblastoma), purely cystic (n = 3, two neuroblastomas, one enteric cyst) and mixed or complex (n = 2, one neuroblastoma and one renal cyst). Three of the fetuses with neuroblastoma had normal scans in the second trimester, and in all four the neuroblastomas were detected after 36 weeks. This study demonstrates the differential diagnosis of suprarenal masses in fetuses. Neuroblastomas can have a solid, purely cystic or complex sonographic appearance. Although not all suprarenal masses are neuroblastomas, the newborn with a prenatally detected suprarenal mass should be evaluated for the possibility of a neuroblastoma, since early diagnosis of this malignancy can be curative.