| C2C | Consumer to Consumer |
| CA | Chartered Accountant |
| CAD | Com­puter Aided Design |
| CAG | Comptroller and Auditor General |
| CARE | Cooperative for American Relief Everywhere |
| CAS | Consolidated Accounts Statement |
| CASE | Commission for Alternative Sources of Energy |
| CAT | Common Admis­sion Test |
| CAZRI | Central Arid Zone Research Institute |
| CBI | Central Bureau of Investigation |
| CBM | Confidence Building Measure |
| CBSE | Central Board of Secondary Education |
| CCEA | Cabinet Committee on Economic Affairs |
| CCS | Cabinet Committee on Security |
| CDAC | Centre for the Development of Ad­vanced Computing |
| C-DAC | Centre For Development of Advance Computing |
| CDMA | Code Division Multiple Access |
| CDRI | Central Drug Research Institute |
| CDS | Compulsory Deposit Scheme |
| CEO | Chief Executive Officer |
| CEPA | Comprehensive Economic Partnership Agreement |
| CFSL | Central Forensic Science Laboratory |
| CGI | Common Gateway Interface |
| CHOGM | Commonwealth Heads of Government Meeting |
| CIA | Central Intelligence Agency |
| CID | Criminal Investigation Department |
| CIS | Commonwealth of Independent States |
| CISC | Complex instruction-set computing |
| CISF | Central Industrial Security Force |
| CITU | Centre of Indian Trade Unions |
| CNG | Compressed Natural Gas |
| CNN | Cable News Network |
| COD | Central Ordnance Depot |
| COFEPOSA | Conservation of Foreign Exchange and Prevention of Smuggling Act |
| COMSAT | Communications Satellite Corporation |
| COPRA | Consumer Protection Act |
| CORBA | Common Object Request Broker Architecture |
| COSC |  Chiefs of Staff Committee |
| CPI(M) | Communist Party of India / Marxist |
| CPO | Central Passport Organization |
| CPRI | Central Power Research Institute |
| CPWD | Central Public Works Department |
| CRIDA |  Central Research Institute for Dry Land Agriculture |
| CRIS | Centre for Railway Information System |
| CRPF | Central Reserve Police Force |
| CRR | Cash Reserve Ratio |
| CSIR | Council of Scientific and Industrial Research |
| CSO | Central Statistical Organization |
| CTBT | Comprehensive Test Ban Treaty |
| CTS | Computerized Tomography Scanner |
| CVC | Central Vigilance Commission |
| CYMK | Cyan, Yellow, Magenta, Kinda |
| D.Lit. | Doctor of Literature |
| D.Litt. | Doctor of Literature |
| D.Phil. | Doctor of Philosophy |
| D.Sc | Doctor of Science |
| DC | Direct Current |
| DCI |  Directorate of Criminal Investigation |
| DDT | Dichloro Diphenyle Tri-chloroethane |
| DFDR | Digital Flight Data Recorder (Black box) |
| DGMO | Director General Military Operation |
| DIG | Deputy Inspector General |
| DISE | District Information System for Education |
| DM | District Magistrate |
| DMA | Direct Memory Access |
| DMICDC |  Delhi Mumbai Industrial Corridor Development Corporation |
| DMK | Dravida Munetra Kazhagam |
| DNA | Deoxyribo-nucleic Acid |
| DPAP | Drought Prone Area Programme |
| DPC | Dabhol Power Company |
| DPSA | Deep Penetration Strike Aircraft |
| DRDO | Defence Research and Development Organization |
| DTH | Direct to Home |
| DTP | Desktop Publishing |
| DVC | Damodar Valley Corporation |
| DVD | Digital Versatile/Video Disc. |