Biochemical and physiological examinations were carried out on the skin surface of the following groups: on 16 newly diagnosed diabetics; on 26 diabetics receiving treatment; and on 2 control groups of 16 and 26 healthy persons respectively of corresponding age and sex. The tests on the surface of the skin of the newly diagnosed diabetics when compared with the corresponding control group show the following significant results: 1. An increase in the percentage of free cholesterol in the lipids of the skin's surface possibly as a result of an increased cell turnover in the epidermis. 2. An increase in the free fatty acid concentration to the disadvantage of the triglycerides in the lipids of the skin's surface as an expression of an improved bacterial lipolysis. 3. A decrease in the reducing substances as confirmed by the phenol-sulfuric acid method in the so called water solubles. 4. An increase in the amino acids as confirmed by the ninhydrin method in the so called water solubles. All the above mentioned changes were more pronounced in the newly diagnosed diabetics than in those already receiving treatment; it can be seen that these changes can partly be normalised under diabetic therapy.