QuickLinks -- Click here to rapidly navigate through this document

Exhibit 21

IMS Health Incorpoated
Active Subsidiaries
As of December 31, 2005

Name					State or Other Jurisdiction of Incorporation	% Ownership 100% except as noted
BATTAERD MANSLEY PTY LTD.					South Africa
COORDINATED MANAGEMENT SYSTEMS, INC.					Delaware
DATA NICHE ASSOCIATES, INC.					Illinois
ENTERPRISE ASSOCIATES, LLC					Delaware
IMS CHINAMETRIK INCORPORATED					Delaware
	IMS Market Research Consulting (Shanghai) Co., Ltd.				China
IMS CHINAMETRIK LIMITED					Hong Kong
	Global Crown Investment Limited				Hong Kong
		United Research China (Shanghai) Ltd.			China
		IMS Meridian Limited			Hong Kong
		IMS Meridian Research Limited			British Virgin Islands
			Meridian Research Vietnam Ltd.		Vietnam
IMS CONTRACT MANAGEMENT SERVICES, INC					Delaware
IMS HEALTH AB					Sweden
	Medical Radar Holding AB				Sweden
		Medical Radar AB			Sweden
IMS HEALTH ASIA PTE. LTD.					Singapore
IMS HEALTH, CANADA LIMITED					Canada
IMS HEALTH DEUTSCHLAND GMBH					Germany
		IMS Health Beteiligungs-gesellschaft mbH			Germany
		IMS Health GmbH & Co. OHG			Germany
			Fricke & Pirk GmbH		Germany
			IMS Hellas Ltd		Greece
			SCICON Wissenschaftliche Unternehmensberatung GmbH		Germany
				SCICON Wissenschaftliche Unternehmensberatung GmbH	Switzerland
IMS HEALTH FINANCE, INC.					Delaware
IMS HEALTH GROUP LIMITED					United Kingdom
	IMS Health HQ Limited				United Kingdom
		IMS Holdings (U.K.) Limited			United Kingdom
			IMS Health Limited		United Kingdom
				IMSWorld Publications Ltd	United Kingdom
				M-Tag Limited	United Kingdom
			Pharma Strategy Group Limited		United Kingdom
			PMS International Limited		United Kingdom
			Cambridge Pharma Consultancy, Ltd.		United Kingdom
				Cambridge Pharma Consultancy, Inc.	Delaware
				PPR Communications Ltd.	United Kingdom
			IMS (UK) Pension Plan Trustee Company Limited		United Kingdom
		IMS Health Surveys Limited			United Kingdom
			IMS Health Networks Limited		United Kingdom
			IMS Hospital Group Limited		United Kingdom
IMS HEALTH INDIA HOLDING CORPORATION					Delaware
	RX India Corporation				Delaware
		IMS Health India Private Limited			India
IMS HEALTH KOREA LTD.					Korea
IMS HEALTH, LDA.					Portugal
	Azyx Servicos de Geomarketing Farmaceutico, Ltda.				Portugal

IMS HEALTH LICENSING ASSOCIATES, L.L.C.					Delaware
	Spartan Leasing Corporation				Delaware	91.00
IMS HEALTH LIMITED					Ireland
	Medical Data Systems Limited				Ireland	70.00
IMS HEALTH PHILIPPINES, INC.					Philippines
IMS HEALTH PUERTO RICO INC.					Puerto Rico
IMS HEALTH S.P.A.					Italy
IMS HEALTH TAIWAN LTD.					Taiwan
IMS HEALTH TRADING CORPORATION					Delaware
	IMS Health Holdings (Pty.) Ltd.				South Africa
		Decision Surveys International (Pty.) Ltd.			South Africa
		IMS Health (Pty.) Ltd.			South Africa
IMS HEALTH TRANSPORTATION SERVICES CORPORATION					Delaware
IMS INFORMATION MEDICAL STATISTICS (ISRAEL) LTD.					Israel
IMS JAPAN K.K.					Japan
	PMSI Japan Ltd.				Japan
IMS NETHERLANDS HOLDING B.V.					Netherlands
	IMS AG				Switzerland
		IMS Health Argentina S.A.			Argentina
			Phama S.A.		Argentina
		Pharmadat Marktforschungs Gesellschaft m.b.H.			Austria
		IMS Health S.P.R.L.			Belgium
			HEDM bvba/sprl		Belgium
			Source Belgium sa/nv		Belgium
		IMS Health Finance Ltd.			Bermuda
		IMS Health Bolivia S.R.L.			Bolivia
		IMS Health Do Brasil Ltda			Brazil
		IMS Bulgaria E.o.o.D.			Bulgaria
		Asesorias IMS Health Chile Limitada			Chile
		Intercomunicaciones Y Servicio de Datos Interdata S.A.			Colombia
		IMS Adriatic d.o.o. za konzalting			Croatia
		IMS Health a.s.			Czech Republic
		IMS Republica Dominicana, S.A.			Republic Dominican
		IMS Ecuador S.A.			Ecuador
		IMS Health Egypt Limited			Egypt
		IMS Health Oy			Finland
		IMS Health S.A.S			France
			Groupe PR		France
				PR International	France
				PR Editions	France
		IMS Software GmbH			Germany
		Asserta Centroamerica Medicion de Mercados, S.A.			Guatemala
		IMS Health Services Ltd			Hungary
		ORG-IMS Research Private Limited			India	50.00
			IMS Health Bangladesh Limited		Bangladesh
			IMS Health Lanka (Private) Limited		Sri Lanka
		PT. IMS Health Indonesia			Indonesia
		UAB IMS Health			Lithuania
		IMS Health Malaysia Sdn. Bhd			Malaysia
		Interdata S.R.L. de C.V			Mexico
		IPP Informacion Promocional y Publicitaria S.A. de C.V.			Mexico
		Informations Medicales & Statistiques S.A.R.L			Morocco
		IMS Health B.V.			Netherlands
		IMS Health Finance B.V.			Netherlands
		IMS Health Norway A/S			Norway
		IMS Health Pakistan (Private) Limited			Pakistan
		IMS Health Paraguaya S.R.L.			Paraguay
		IMS Health Del Peru S.A.			Peru
		Azyx Polska Geopharma Information Services, Sp.z.o.o			Poland

		IMS Poland Limited Sp.z.o.o.			Poland
		IMS Pharmaceutical Services Srl.			Romania
		IMS Information Medical Statistics, spol.s.r.o.			Slovak Republic
		IMS Services, pharmaceutical marketing services Ltd.			Slovenia
		IMS Health, S.A.			Spain
		IMS Production Hubs, S.L.			Spain
		Mercados Y Analisis, S.A.			Spain
		Areks			Switzerland
			Areks Japan K.K.		Japan
			Areks US, Inc.		Delaware
		CORE Holding GmbH			Switzerland
			CORE Center for Outcomes Research GmbH		Switzerland
			CORE-USA LLC		Indiana
		IMS Health GmbH			Switzerland
		M&H Informatics Holding AG			Switzerland
			ACCELETRA AG		Switzerland
			M&H Informatics AG		Switzerland
			M&H Informatics (BD)		Bangladesh
			TeamBridge AG		Switzerland
		Interstatistik AG			Switzerland
			Datec Industria e Comercio, Distribuidora Grafica e Mala Direta Ltda.		Brazil
			IMS Health Marktforschung GmbH		Austria
		IMS Health Tunisia sarl			Tunisia
		IMS Health Tibbi Istatistik Ticaret ve Musavirlik Ltd Sirketi			Turkey
		IMS Health Uruguay S.A.			Uruguay
		PMV De Venezuela, C.A.			Venezuela
IMS SERVICES, LLC					Delaware
	IMS Health (Australia) Partnership				Australia
		IMS Health Australia Holding Pty. Ltd.			Australia
			IMS Health Australia Pty. Ltd.		Australia
			M-Tag Pty. Limited		Australia
			Battaerd Mansley Pty. Ltd.		Australia
				Battaerd Mansley India Private Limited	India
			IMS Health (N.Z.) Limited		New Zealand
IMS SOFTWARE SERVICES, LTD.					Delaware
	Infoplex GmbH				Germany
INTERCONTINENTAL MEDICAL STATISTICS INTERNATIONAL, LTD. (DE)					Delaware
MARKET RESEARCH MANAGEMENT, INC.					Delaware
949122 ONTARIO INC. (MEDCOM)					Canada
PHARMETRICS, INC.					Massachusetts
ROSENBLATT-KLAUBER GROUP, INC.					Vermont
ROSENBLATT-KLAUBER GROUP CANADA INC.					Canada
SOURCE INFORMATICS LIMITED					United Kingdom
IMS GOVERNMENT SOLUTIONS, INC.					Virginia

QuickLinks

IMS Health Incorpoated Active Subsidiaries As of December 31, 2005