ABSRACT: Cosmetic products should be safe under normal or reasonably foreseeable conditions of use. The regulation on cosmetic products (EC 1223/2009) requires for the cosmetic product safety report the results of preservation challenge test to prove the microbiological safety. The regulation itself didn’t specify the test procedure for the challenge test. Beside the test from the EU and US pharmacopoeia in-house test protocols are established since many years. The applicability of the schülke KoKo test for the evaluation of the microbiological safety of finished cosmetic products is assessed in this paper.