| Cloud Technologies S.A. | |
| CloudBest | |
| CloudFerro S.A. | |
| Clouds On Mars Sp. z o.o. | |
| Cloudstate | Masovian |
| CloudTech Solutions | |
| Club Net | Silesian |
| COBIN Angels | |
| Codahead | |
| Code Apps | |
| Code Europe | |
| Code Quest Sp. z o.o. | |
| Code Sprinters | |
| CODE:ME | |
| CodeAgency.pl | |
| CodeAll | |
| CodeBeat | |
| CodeConcept | |
| Codefia Sp. z o.o. | |
| CodeJungle | |
| Codelabs.rocks | |
| CodeLabs.SH | Silesian |
| Codemachine Sp. z o. o. | Lower Silesian |
| Codemask | |
| Codeminded Software House | Lower Silesian |
| Codenest | Lesser Poland |
| Coderion Sp. z o.o. | |
| Coders Lab | Masovian |
| CodeRunner IT | |
| Codetain | |
| Codete Global Sp. z o.o. | |
| CodeTwo | Lower Silesian |
| CodeWave | Lower Silesian |
| Codewise Sp. z o.o. Sp. k. | Lesser Poland |
| Codibly | |
| Cognitiva | |
| Cognitum | |
| COIG S.A. | Silesian |
| Colaborawork.pl | |
| Coldlight Creative | Lesser Poland |
| CoLegal | |
| Collegium Balticum | |
| Collegium Civitas | Masovian |
| Collegium Da Vinci | Greater Poland |
| Collegium Witelona Uczelnia Państwowa | |
| Columbus Energy S.A. | |
| Comarch S.A. | Lesser Poland |
| ComDevelop | Silesian |
| COMES Sp. z o.o. | Lower Silesian |
| Cometari | Lesser Poland |