ABSTRACT: The first edition of ISO 11930 (1) was published in April 2012 under the title »Cosmetics – Microbiology – Evaluation of the antimicrobial protection of a cosmetic product«. This test can be used to evaluate the preservation of a cosmetic formulation. While the regulation on cosmetic products (EC 1223/2009) (2) requires that the cosmetic product safety report demonstrates the results of preservation challenge test to prove the microbiological stability, it does not specify the test procedure for the challenge test. In addition to ISO 11930 tests from the EU (3) and US pharmacopoeia (4), the ASEAN preservative efficacy test (5), the test from the CTFA Microbiology Guidelines (6) as well as several in-house test protocols have been established for many years. This paper includes a comparison of the different methods and comparative test results for ISO 11930, Ph. Eur. 7 and the schülke KoKo Test.