A hydroptic newborn was born at 32 weeks' gestation and at the age of 14 h died of post-asphyxial syndrome. Immunologic causes of hydrops fetalis were excluded, as were anomalies and chromosomal aberrations. Ureaplasma urealyticum was isolated in bronchial secretions, lung tissue and brain tissue of the newborn. Our findings suggest that U. urealyticum infection should be considered in the differential diagnosis of hydrops fetalis.