During the 1990s, the health care community developed a taxonomy to define the structures and strategies of newly emerging health care organizations. Since the 1990s, however, health care has undergone significant changes, and the differences in health care now and health care ten years ago raises the question of whether the taxonomy for evaluating health care structures still applies. This article revisits the taxonomy of health networks and systems to: (1) assess how cluster categories of hospital-led health care changed over time, (2) identify new patterns and (3) demonstrate how new data can help modify taxonomy measures. To accomplish this, the authors applied three strategic dimensions (differentiation, integration and centralization) to three components of the health service continuum (hospital services, physician arrangements and provider-based insurance activities). For this analysis, the authors used a data sample of 216 health networks and 342 health systems from the 1998 American Hospital Association Annual Survey of Hospitals. The results of this study indicate that while there is some realignment of categories along certain structural dimensions, on the whole the taxonomy parameters (differentiation, integration, centralization, etc.) have stood up well over time. As it is refined and modified, the taxonomy will provide policymakers and practitioners with a descriptive and contextual framework from which to assess organizational programs and policies, aiding in overall quality improvement. This research provides a base and precedent for future research examining such things as the impact of technology and communications, as well as continuing to revisit the taxonomy from time to time.