Among the types of intellectual property rights covered by the TRIPS Agreement, WTO Members must, pursuant to Article 39.3, protect certain test and other data submitted “as a condition of approving the marketing of pharmaceutical or of agricultural chemical products.” Such protection provides the incentives necessary for the biopharmaceutical industry to conduct the lengthy, expensive multi-phased clinical testing that is required to demonstrate the safety and effectiveness of a new drug or vaccine. Test data protection has become increasingly more important to the development of new medicines in the past several years. That is in significant part because biologics (i.e., large chemical molecules such as proteins, made by biotechnology) have revolutionized medicine with more effective treatments for cancer, rheumatoid arthritis, asthma, and other diseases. To deliver on their full potential for patients, biologics need a sufficient period of test data protection. This article first sets out the proper interpretation of Article 39.3 of the TRIPS Agreement, highlighting the critical flaws in the interpretations set out by several academics and international organizations over the past several years. Then, the sections that follow consider specific examples of how the obligations in Article 39.3 have been interpreted and, in fact, implemented over the past quarter-century, and evaluate the consistency of such interpretation and implementation with the proper interpretation of that provision. In particular, Section III looks to countries that have clarified and, in some instances, expanded the coverage and scope of Article 39.3, including through Free Trade Agreements (“FTAs”), some of which include so-called “TRIPS- plus” provisions. Section IV then considers countries that have reportedly failed to faithfully implement the requirements of Article 39.3, whether through a deficiency in their laws and regulations, or through a failure to enforce or implement laws and regulations that otherwise would appear on their face to satisfy Article 39.3. Section V provides concluding remarks about the state of global protection of test data, and the way forward.