<Page>
EXHIBIT 21

IMS HEALTH INCORPORATED
ACTIVE SUBSIDIARIES
AS OF DECEMBER 31, 2001

<Table>
<Caption>
STATE OR OTHER % OWNERSHIP
JURISDICTION OF 100% EXCEPT
NAME INCORPORATED AS NOTED
- ---- ---------------------- ------------

COGNIZANT TECHNOLOGY SOLUTIONS CORPORATION Delaware 58.29
Cognizant Technology Solutions U.S. Corporation Delaware
Cognizant Technology Solutions Canada, Inc. Canada
Cognizant Technology Solutions Germany GmbH Germany
Cognizant Technology Solutions India Limited India
Cognizant Technology Solutions UK Limited United Kingdom
CSS Investment Corporation Delaware

COORDINATED MANAGEMENT SYSTEMS, INC. Delaware

DBHC, INC. Delaware
LexHealth, Inc. Illinois

ENTERPRISE ASSOCIATES, LLC Delaware

IMS AG Switzerland
IMS Health Licensing Associates, L.P. Delaware 87.85
Spartan Leasing Corporation Delaware
PMA Sociedad Anonima Argentina
IMS Health Marktforschungs G.m.b.H. Austria
Pharmacall Statistik Ges.m.b.H. Austria
IMS Health Bangladesh Limited Bangladesh
IMS Health S.A. Belgium
IMS Health Finance Ltd. Bermuda
Pharma Data Boliviana S.R.L. Bolivia
IMS Health Do Brasil Ltda. Brazil
Asesorias IMS Health Chile Limitada Chile
Intercomunicaciones Y Servicio de Datos S.A. Colombia 98.96
IMS Medinform A.S. Czech Republic
IMS Republica Dominicana, S.A. Dominican Republic
Datandina Ecuador S.A. Ecuador
IMS Egypt Limited Egypt
IMS HEALTH Oy Finland
IMS HEALTH S.A. France
Logimed S.A.S. France
Source Informatics S.A.S. France
Asserta Centroamerica Medicion de Mercados, S.A. Guatemala
IMS Health Services Ltd. Hungary
PharmaFELAX Commerical Ltd. Hungary
UAB IMS Health Lithuania
IMS Health Malaysia Sdn. Bhd. Malaysia
Interdata S.A. de C.V. Mexico
IPP Informacion Promocional y Publicitaria S.A. de C.V. Mexico
Informations Medicales & Statistiques S.A.R.L. Morocco
I.M.S. Health B.V. Netherlands
I.M.S. Finance (Nederland) B.V. Netherlands
IMS Health Norway A/S Norway
Pharma Data Paraguaya S.R.L. Paraguay
IMS Health Del Peru S.A. Peru
</Table>

29
<Page>

<Table>
<Caption>
STATE OR OTHER % OWNERSHIP
JURISDICTION OF 100% EXCEPT
NAME INCORPORATED AS NOTED
- ---- ---------------------- ------------

IMS Poland Limited Sp.z.o.o. Poland
IMS Information Medical Statistics, spol.s.r.o. Slovakia
IMS Health, S.A. Spain
Mercados Y Analisis, S.A. Spain
IMS Lanka (Private) Limited Sri Lanka
IHA.IMS Health GmbH Switzerland 50.00
Interstatistik AG Switzerland
IMS Ges.m.b.H. Austria
Datec Industria e Comercio, Distribuidora Grafica e Mala Brazil
Direta Ltda.
IMS Tunisia Tunisia
IMS Tibbi Istatistik Ticaret ve Musavirlik Ltd Sirketi Turkey
Pharma Data Uruguaya S.A. Uruguay
PMV De Venezuela, C.A. Venezuela

IMS CHINAMETRIK LIMITED Hong Kong
IMS Meridian Limited Hong Kong
Meridian Research Limited British Virgin Islands
Meridian Research Vietnam Ltd Vietnam

IMS CHINAMETRIK INCORPORATED Delaware

IMS HEALTH ASIA (1989) PTE. LTD. Singapore

IMS HEALTH AUSTRALIA PTY. LTD. Australia
Farmer Crow Pty. Limited Australia
Chemdata Pty. Limited Australia
Data Design Hisoft Pty. Limited Australia
Medrecord Australia Pty. Limited Australia
Healthnet Pty. Limited Australia

IMS HEALTH, CANADA LIMITED Canada

IMS HEALTH DEUTSCHLAND GMBH Germany
IMS-MIDOC Medizinische Informations-Dokumentations und Germany
Consultinggesellschaft mbH
IMS Health Beteiligungs-gesellschaft mbH Germany
IMS Health GmbH & Co. OHG Germany
GPI Krankenhaus-forschung Gesellschaft Fur
Pharma-Informationssysteme mbH Germany
IMS Hellas Ltd. Greece

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
Medical Direct Mail Organisation Ltd. 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
PMSI UK Limited United Kingdom
IMS Health Networks Limited United Kingdom
PMSI Medical Research Factors Limited United Kingdom
Medicare Audits Limited United Kingdom
</Table>

30
<Page>

<Table>
<Caption>
STATE OR OTHER % OWNERSHIP
JURISDICTION OF 100% EXCEPT
NAME INCORPORATED AS NOTED
- ---- ---------------------- ------------

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

IMS HEALTH (NZ) LIMITED New Zealand

IMS HEALTH PHILIPPINES, INC. Philippines

IMS HEALTH PUERTO RICO INC. Puerto Rico

IMS HEALTH S.P.A. Italy

IMS HEALTH TRADING CORPORATION Delaware
IMS Health (Pty.) Ltd. South Africa
Decision Surveys International (Pty.) Ltd. South Africa
PMSA (Pty.) Ltd. South Africa

IMS HEALTH TRANSPORTATION SERVICES CORPORATION Delaware

IMS INFORMATION MEDICAL STATISTICS (ISRAEL) LTD. Israel

IMS JAPAN K.K. Japan
PMSI Japan K.K. Japan

IMS SOFTWARE SERVICES, LTD. Delaware

IMS TAIWAN COMPANY LTD. Taiwan

INTERCONTINENTAL MEDICAL STATISTICS INTERNATIONAL, LTD. (DE) Delaware

IMS HEALTH LIMITED Ireland
Medical Data Systems Limited Ireland

I-SQUARED, INC. Delaware

SOURCE INFORMATICS EUROPE B.V. Netherlands

SOURCE INFORMATICS LIMITED United Kingdom
</Table>