Purpose In this study, tests for efficacy of biocide treated articles are assessed Method In this study, national and international legislation and practices in the countries of the European Union and OECD are reviewed. Findings The range of treated articles and treated materials produced is vast. However, they all share one property in common in that they are intended to express some sort of function against biological systems in service. Articles treated with biocides can be divided in two major groups: one where the biocide preserves the functions of the article itself, the other where new properties are introduced by the biocidal treatment. It is very important to provide guidance on the efficacy testing of biocides used in materials and treated articles. It aims to help define the problem that the use of a biocide is intended to solve or the property that it is intended to introduce and why that is required. One of the fundamental pre-requisites for understanding the role that a biocidal active substance/product must fulfil is an understanding of the problem that their use is intended to either resolve or, at least, mitigate. The end use and performance required affect not just the concentration of active substance(s), but also the way they interact with their surroundings (emissions to the environment, skin, food, the possibility of resistance being developed to an active substance or, more significantly, cross resistance with active substances used for clinical purposes etc.) and are important for judging the risk vs. benefit balance according to the OECD studies. Result With certain biocidal products such as disinfectants, there are many national and regional performance criteria that are employed to determine how effective a product needs to be under a certain set of conditions.