In 7-day chick embryo dorsal root ganglia and epidermis or dermis co-cultures, nerve fibres establish contacts with dermis while avoiding epidermis. Previous results have indicated that factor(s) secreted by epidermis could be involved in this avoidance reaction. The present study demonstrates that the avoidance reaction is abolished when epidermal cells are treated by the N-linked glycoproteins synthesis inhibitor, tunicamycin. The same result is obtained after monensin treatment. The epidermal cell viability, development and total protein secretion are not significantly affected by tunicamycin, as demonstrated by trypan blue exclusion, electron microscopy and SDS-PAGE electrophoresis after 35S-methionine labelling. It has thus been concluded that the avoidance factor is glycoproteic in nature. It is also suggested that this factor possibly contains chondroitin-6-sulphate moieties.