| COEX | |
| Coinstelegram media group | |
| CoLab | |
| Comfortel | Saint Petersburg |
| Commfort Software Ltd | Novosibirsk |
| Computer Help | Smolensk |
| Console | Novosibirsk |
| Content Labs | Moscow |
| Continent Telecom | Moscow |
| Contour Maps | Moscow |
| CoolUtils | Moscow |
| Corporate University of Moscow Education | |
| CPS | Moscow |
| CPS Labs Ltd | Mari El |
| Craft Talk | |
| CreateInstall | Moscow |
| CreativeSOFT | Moscow |
| Creators | |
| CREDO Consulting | |
| CredoDesign | Sevastopol |
| Crimean Engineering and Pedagogical University named after Fevzi Yakubov | |
| Crosstech Solutions Group | |
| CrowdSystems | |
| Crystal Office Systems | Moscow |
| Crystal Rich Ltd | Saint Petersburg |
| Cubase.su | Moscow |
| Cusoft | Moscow |
| Cyber Polygon | Moscow |
| Cybercom Ltd | |
| CyberFT | |
| Cyberian.tech | |
| CyberLife | Moscow |
| Cyberslab | |
| CyD Software Labs | Rostov |
| CYPIX | |
| Cпутниковое оборудования в Калуге | Kaluga |
| Cхідноукраїнський національний університет імені Володимира Даля | Luhansk People's Republic |
| Da Vinci Capital LLC | Moscow |
| Dagestan State Technical University | |
| Daniil One | |
| Danilin.biz | |
| DaOffice | |
| Data East, LLC | Novosibirsk |
| DataArmor | |
| DataFabric | |
| Dataforce | Moscow |
| DATARC | |
| Datatel | |
| DATUM Soft | |
| DC Lite | |