St. Vincent's Hospital in New York City was the primary recipient of patients after the 1993 bombing of the World Trade Center. This experience prompted the drafting of a formal disaster plan, which was implemented during the terrorist attack on the World Trade Center on September 11, 2001. Here, we outline the Emergency Management External Disaster Plan of St. Vincent's Hospital and discuss the time course of presentation and medical characteristics of the critically injured patients on that day. We describe how the critical care service adapted to the specific challenges presented and the lessons that we learned. We hope to provide other critical care systems with a framework for response to such large-scale disasters.