Summary A case of enophthalmos with blow-out fracture of the medial orbital wall and of the floor of the orbit in a 15-year-old boy is presented. Only very few authors have published an operative procedure for this lesion. Reconstruction of the medial orbital wall fracture was achieved by inserting a preformed allograft into the ethmoidal space after clearing out the ethmoidal cells via an antral approach. The procedure, advantages and possible dangers are discussed.