This document specifies the procedure for the assessment of medical devices and their constituent materials with regard to their potential to produce irritation. The tests are designed to predict and classify the irritation potential of medical devices, materials or their extracts according to ISO 10993-1 and ISO 10993-12. This document includes: pre-test considerations for irritation, including in silico and in vitro methods for dermal exposure; details of in vitro and in vivo irritation test procedures; key factors for the interpretation of the results. Instructions are given in Annex A for the preparation of materials specifically in relation to the above tests. In Annex D several special in vivo irritation tests are described for application of medical devices in areas other than skin. In addition, Annex E provides information for conducting human skin irritation testing.