| Cloud Centric | |
| CloudHero | Bucharest |
| Cluj IT Cluster | Cluj |
| Cluj Makers | Cluj |
| Cluj Startups | |
| ClusterCS | |
| Clusterul Regional Inovativ de Imagistică Moleculară şi Structurală Nord-Est | Iași |
| Code Noir | Brașov |
| Code School Clubs | |
| Codecamp Romania | |
| Codefy Software | Iași |
| CodeMix S.R.L. | |
| CoderDojo | Bucharest |
| CoderDojo România | |
| Codespring | |
| Codette | |
| Codiax | Cluj |
| cognitive SEO Internet Marketing Tools | Iași |
| Coindoo | |
| Combridge | Bucharest |
| Comknow | Cluj |
| Commons | |
| Compact Studio | Cluj |
| Competitors App S.R.L. | |
| Compusoft | Bucharest |
| Compusoft Prod S.R.L. | Bucharest |
| Computer Expert | Bucharest |
| Computer Solution | Iași |
| ComputerLand Romania | Bucharest |
| Computers Group | Bacău |
| Computerscom | Alba |
| Comrace Computera | Dolj |
| Comunicaţii mobile | Bucharest |
| Concept24 Online S.R.L. | Bucharest |
| ConcretConsult S.R.L. | Bucharest |
| Conectiva | Bucharest |
| Conectoo | |
| Confidas | |
| Connect Romania | Bucharest |
| Connections Consult S.A. | |
| Connsys | |
| Consi Serv | Dolj |
| Consoft | Bucharest |
| Consult Line | |
| Conta Pro | Bucharest |
| ContentSpeed | Bucharest |
| Contimar Consulting | Bucharest |
| ConturSoft | |
| Convex Network | |
| Copier Tech S.R.L. | Bucharest |