| bsscommunication.com | Masovian |
| BST | Silesian |
| BTC Sp. z o.o. | West Pomeranian |
| Buddy Team Sp. z o.o. | Masovian |
| Buisness Insider Polska | |
| Bull Design | Masovian |
| Bunker Studio | Masovian |
| Bürkert Contromatic GmbH | Masovian |
| Buro S.C. | Masovian |
| Business Lab Nowy Świat s.c. | |
| BUTORG Sp. z o.o. | Lower Silesian |
| bValue Fund | |
| Byss Mobile | |
| byteLAKE | |
| C&C Partners Telecom Sp. z o.o. | Greater Poland |
| CA Consulting | |
| CAD-Project | Lower Silesian |
| CAD.pl | Silesian |
| CAD/CAM Solution Sp. z o.o. | |
| CafeSuite | Łódź |
| CAIRO-soft Sp. z o.o. | Warmian-Masurian |
| CaixaBank S.A. | |
| CallPage | |
| Callstack.io Sp. z o.o. | |
| Cancer Center AI | |
| CANEA Inżynieria i Komputery | Świętokrzyskie |
| Canon Polska Sp. z o.o. | Masovian |
| Capital One Advisers Sp. z o.o. | |
| Capital Service S.A. | |
| Caps | Masovian |
| Captor Therapeutics S.A. | |
| Cardinal Cryptography Sp. z o.o. | Lesser Poland |
| Cardio 4D | |
| Cardiomatics | |
| Cargill | |
| Cargounit Sp. z o.o. | |
| Carpathia Capital | Greater Poland |
| Carrywater Group S.A. | Masovian |
| CashDirector S.A. | |
| Casp System sp. z o.o. | Silesian |
| Cassini | Masovian |
| CBIT Sp. z o.o. | Masovian |
| CD Projekt S.A. | |
| CDN-Partner w Krakowie Sp. z o.o. | |
| cdnet | Lesser Poland |
| CDRmarket | Silesian |
| Cellco Communications Sp. z o.o. | West Pomeranian |
| CelNet | Pomeranian |
| Celon Pharma S.A. | |
| Cemit | Masovian |