Hypoechoic hepatomegaly associated with transient abnormal myelopoiesis provides clues to trisomy 21 in the third-trimester fetus.

We present two cases of transient abnormal myelopoiesis associated with trisomy 21 that had hypoechoic hepatomegaly during the late fetal period. Fetal chromosomal abnormality and fetal myeloproliferative disorder should be suspected in such cases.