Two fetuses with severe bilateral renal hypoplasia are described; both diagnoses were made following elective abortion for oligohydramnios and suspected renal dysplasia. A 20-week female fetus (46,XX) had pulmonary hypoplasia and very small kidneys (7% of expected weight) that were normally shaped and nondysplastic, with well-formed medullae and metanephric blastema and markedly diminished cortices with only rare glomeruli. A 23-week male fetus (46,XY) had small kidneys (13% of expected weight) that were nondysplastic, normally shaped, and histologically well organized with moderately decreased numbers of glomeruli. Isolated bilateral renal hypoplasia has not previously been well characterized in fetuses; the presence of oligohydramnios (both cases) and pulmonary hypoplasia (one case) suggests that this finding is associated with impaired fetal renal function and may adversely influence neonatal survival.