This document provides information on key elements of a PRTR to national governments that are designing new PRTRs or considering revising an existing PRTR and describes considerations for developing PRTR systems whose data are compatible and can be integrated with data from other PRTRs for global scale analysis. For each element, this document compares how existing PRTRs have been designed, presents recommendations from the OECD Council on Implementing PRTRs, and provides options for designing a PRTR that 1) meets the needs of the country implementing the PRTR, and 2) collects data that are harmonised with data from existing PRTRs where possible. This document is also useful for users of PRTR data, particularly those who use PRTR data from different PRTRs. Those who plan to examine different PRTR data can consider the points raised in this document. In this document the terms “harmonise” and “harmonisation” means to make compatible, miscible or combinable. Similarly, the term “harmonised” means to be compatible, miscible, combinable, or combined (integrated).