The composition of DNA-binding proteins (DBP) was shown to be tissue-specific and to vary at different stages of gene expression. As the accelerated epidermopoesis in psoriasis indicates changed gene activities, DBP of psoriatic scales were compared with those of normal human epidermis, dermis and horny layer. Each skin fraction is characterized by its own DBP pattern, indicating different cell species. 1. The DBP of normal human epidermis shows only a small accordance with the DBP of human dermis and implies their difference in origin, function and cell types. 2. Psoriatic scale DBP and epidermal DPB contain more corresponding proteins which can be deduced from the scale's origin from epidermis. However, the composition of all proteins differs to a great extent. This either occured during parakeratotic keratinization or reflects differences of normal to psoriatic epidermis. Imposing for psoriatic scale DBP are two protein bands with molecular weights of 84,000 and 90,000 daltons. Evidently both are not present in the DBP of other skin layers. 3. The horny layer contains a very small amount of DBP which might represent DNases to a major part. The small DBP content in horny layer confirms the previous supposition of psoriatic scales, to be mostly derived from the preserved nuclei of the parakerototic scale layer.