The authors monitored the implementation of the Health Insurance Portability and Accountability Act (HIPAA) from 1997 to 1999. Regulators in all states and relevant federal agencies were interviewed and applicable laws and regulations studied. The authors found that HIPAA changed legal protections for consumers' health coverage in several ways. They examine how the process of regulating such coverage was affected at the state and federal levels and under an emerging partnership of the two. Despite some early implementation challenges, HIPAA's successes have been significant, although limited by the law's incremental nature.