| Business Angels Greece | |
| Business Cloud | |
| Business Effect Α.Ε. | |
| Butler Chat Ι.Κ.Ε. | |
| Byte Computer ABEE | Attica |
| Cantaloop | |
| Carge | |
| Census S.A. | Attica |
| Centiva | |
| Centre for Renewable Energy Sources and Saving | |
| Centre for Research & Technology Hellas | |
| CeoworldMagazine | Attica |
| cforce | Attica |
| CGSoft | |
| Check-Domains.com | North Aegean |
| Chilloutapps | Attica |
| CIELinc. | |
| CITY College, University of York Europe Campus | |
| City Unity College Department of Computer Science | |
| Citycom | Attica |
| Cloudhaz | Epirus |
| CloudSystems | |
| CMD Digital Agency | Attica |
| Code.Hub | Attica |
| CodeBlocks | Attica |
| Collectives S.A. | |
| College Year in Athens | |
| Compucon S.A. | Central Macedonia |
| Computer Control Systems S.A. | Attica |
| Computer Life | Attica |
| Computer Life S.A. | Attica |
| Computer Technology Institute & Press | Attica |
| ComputerMind S.A. | Attica |
| Comsys | Attica |
| Concel Systems | Attica |
| Connexion3 | Attica |
| Contact Solutions Ltd | Attica |
| ContactPigeon | Attica |
| Cope Digital Agency | |
| Corallia | |
| CoreConcepts | |
| Cosmodata | Attica |
| Cosmolink | |
| Cosmos Business Systems | |
| Cosmote.gr | Attica |
| CPI Computer Peripherals International | Attica |
| Crazysoft.gr | Attica |
| Creations.gr | Attica |
| Creative People | Attica |
| CretaForce Internet Services | Attica |