Proper health surveillance is vitally important to the evaluation of the microbial status of laboratory animals and the performance of standardized experiments with a minimum number of animals. Sufficient and reliable information about animals health status has become even more important during the last decade with the rapid development and worldwide exchange of new genetically modified rodents. But a universal testing strategy for the assessment of pathogen status in rodent populations and internationally recognized standards and definitions of their quality do not exist, even though health data can provide consistent information only when based on systematic sampling and testing. Although there have been repeated calls for the development of international health monitoring standards and reporting, there are also objections. This article presents both the advantages and limitations of guidelines. After an overview of major factors to consider I discuss previous attempts to harmonize health monitoring procedures. The health monitoring recommendations for rodents issued by the Federation of European Laboratory Science Associations (FELASA) could serve as a model for global recommendations and for international harmonization. Given the increased significance of accurate health information when exchanging animals, research institutions and universities would benefit from universal standards, which would also help scientists as well as reviewers and readers of publications to better assess the validity of research results.