857 non-dermatologic patients were patch-tested with the Finn-Chamber-technique. The sequent testings under identical conditions were made after 3-12 months. Readings were done after 24, 72, 96 hours and later. During the first test-series we found 44 reactions to be positive, 20 remained identical during repetition-testings, 7 became negative and 36 positive reactions appeared. So reproducibility was 46% for the positive results of the first testing serie.