On 73 patients suspected for atopic diseases, 258 skin tests and radioallergosorbent tests (RAST) for specific IgE in serum were carried out. The results of both tests were compared in connection with the clinical picture. A good qualitative positive correlation was found, especially for grass pollen and house dust. False positive results with RAST cannot be excluded. The RAST seems to be a valuable adjunct to extensive allergologic diagnostic investigation, particularly in cases where difficulties can be expected in the performance or the interpretation of skin tests.