The present study investigates at the light and electron microscopic levels the possible presence and distribution during human development of glial-like satellite cells in sympathetic neural crest derivatives by S-100 immunohistochemistry. From the earliest stages investigated, immunostained cells were detected inside sympathetic migrating masses and at their periphery, where they constituted a continuous layer isolating sympathetic elements from mesenchymal cells. The detection and peculiar distribution of these glial-like cells in developing sympathetic tissue could open new perspectives in the study of events linked to the migration and differentiation of some neural crest derivatives.