Approaches to categorize uses of chemical substances vary between countries, although a system for describing the uses of chemicals is an essential element in assessing exposure of humans and the environment to those chemicals during their use. To facilitate the exchange of information across countries, this document proposes harmonized functional use categories and product and article use categories. The lists consist of 107 functional use categories, 91 product use categories and 69 article use categories. Each category is accompanied by a definition and examples of products, where appropriate, that should be reported under that category; the examples are intended to provide clarity in selection of a category thereby minimizing overlap and improving accuracy. Countries are encouraged to incorporate the updated codes in exposure assessments, exposure models and databases, and in reporting use information.