The "D. E. F.-syndromes" consist of ectodermal dysplasia, cleft of the lip and/or palate (fente labiale et/ou palatine). This group includes the A. E. C.- and the E. E. C.-syndromes. We are reporting two cases of D. E. F.-syndrome, in which there was a very particular hair dysplasia, which we named "scrubbing-brush hair". The first case was a boy. The disease was probably transmitted on the dominant autosomal mode. The ectodermal dysplasia was of hypohidrotic type. The second case was also observed in a boy. There was no similar genetic abnormality in the family. The ectodermal dysplasia was of hidrotic types. The embryological findings account for the association between the ectodermal dysplasia and the medial dysraphia of the face.