Pollutant release and transfer registers (PRTRs) are becoming a popular measure for addressing industrial pollution in many countries. PRTRs require reporting of emissions from specific industrial sectors and making the information publicly available. This article suggests a framework for comparing PRTRs in order to determine whether they attain their declared goals and which factors, if any, influence their effectiveness. The challenges to such a comparison can be divided into three groups. The first refers to changes that are directly linked to the characteristics of PRTRs: both the changes within a specific system over time and variations among different systems. The second refers to parameters that affect the outcomes of the systems without being directly a part of them. The third involves the relations between the emissions reported to the PRTRs and the associated environmental risk. We suggest an approach that relies on relative comparison, commensurate with the unique characteristics of each PRTR, that compares their actual outcomes. Such an approach is necessary both due to significant variations among current PRTRs as well as for following the unique policy objectives that are manifested in different PRTRs. Application of this comparative approach in the United States, England, Canada, and Australia demonstrates significant differences in PRTR systems across countries and suggests that the mere presence of a PRTR may not lead to reduced industrial emissions. The analysis also demonstrates that emission reductions do not correlate with reductions in risk-related measures. The article proposes several simple modifications to the composition of current PRTR databases that may facilitate more accurate analysis of results and effective oversight of implementation.