1 EXHIBIT 21 SUBSIDIARIES OF THE REGISTRANT Eclipsys Solutions Corp., a corporation organized under the laws of the State of Delaware. SDK Medical Services Corporation, a corporation organized under the laws of the Commonwealth of Massachusetts. Emtek Healthcare Corporation, a corporation organized under the laws of the State of Delaware. Eclipsys International Corp., a subsidiary of Eclipsys Solutions Corp. and a corporation organized under the laws of the State of Delaware. Eclipsys Limited, a subsidiary of Eclipsys Solutions Corp. and a limited company organized under the laws of England and Wales. Transition Systems, Inc., a corporation organized under the laws of the Commonwealth of Massachusetts. HealthVISION, Inc., a corporation organized under the laws of the State of Delaware. PowerCenter Systems, Inc., a corporation organized under the laws of the State of Delaware.