We report on four autopsy cases of Potter's syndrome associated with characteristic Potter's face, pulmonary hypoplasia, and renal agenesis or dysplasia. There were no pathologic differences in typical cases with bilateral renal agenesis and variant cases with renal dysplasia instead of renal agenesis. All cases showed bilateral pulmonary hypoplasias and immature lung microscopically. Hyaline membrane disease was found in three cases in spite of late gestation. In one case with renal dysplasia, disaturated phosphatidylcholine, a pulmonary surfactant phospholipid, was measured and found to be decreased in comparison with that in age-matched controls. This suggests that functionally immature lung may be one feature of Potter's syndrome that is similar to hyaline membrane disease.