Estrogen receptor-like immunoreactivity (ER-LI) was detected in the medial subnucleus of the facial nucleus by immunocytochemistry in both male and female neonatal rats, but not in the adult rat. Identity of the motoneurons in this subnucleus projecting to the corresponding facial muscles and the cells with ER-LI positive signals was examined by retrograde tracing. The majority of the cells marked with the tracer did not carry ER-LI signals.