Three exercises of The Plan to Coordinate NEHRP Post-Earthquake Investigations were developed and implemented in late 2003 and early 2004 in order to test the Plan itself via realistic scenarios, and for the NEHRP agencies to learn how to coordinate post-earthquake investigations. The exercises were selected to cover a range of seismic activity and consequences, and were based on scenario events: (1) a Hayward Fault Mw 7 event without foreshocks; (2) a New Madrid seismic zone Mw 7 event with foreshocks, and (3) a Puerto Rico Mw 8 subduction event on the Puerto Rican Trench accompanied by a tsunami affecting the eastern seaboard of the United States. Each exercise consisted of a four-hour telephone conference call with a Web-based electronic link and post-exercise evaluations fed back to participants. Evaluation of the exercises found the Plan to be adequate, with implementation of the Plan by the NEHRP agencies improving with each exercise. Based on the exercises, recommendations were provided that a Plan coordinator should be designated within USGS, an annual exercise of the Plan should be conducted in different regions of the United States, a permanent NEHRP electronic link should be created, and coordination of post-earthquake data collection, preservation, archiving, and dissemination should be greatly improved.