| Navn | Postnummer | By |
|---|---|---|
| C.K. Produktion | 7190 | Billund |
| Cabcongroup | 2605 | Brøndby |
| Carl Zeiss A/S | 3460 | Birkerød |
| Carsten Holm A/S | 5750 | Ringe |
| CB Svendsen A/S | 3500 | Værløse |
| CCM Electronic Engineering | 6400 | Sønderborg |
| Celltech A/S | 3500 | Værløse |
| ComSystem A/S | 3490 | Kvistgård |
| Condair A/S | 8680 | Ry |
| Coromatic A/S | 4000 | Roskilde |
| Cre8tek Denmark ApS | 9800 | Hjørring |