| C K Produktion A/S | 7190 | Billund |
| CAD Kompagniet A/S | 2730 | Herlev |
| Cadskolen A/S | 9000 | Aalborg |
| Carl Stahl A/S | 7000 | Fredericia |
| Carl Zeiss A/S | 3460 | Birkerød |
| Carlo Gavazzi Handel A/S | 8370 | Hadsten |
| Carsten Holm A/S | 5750 | Ringe |
| CB Svendsen A/S | 3500 | Værløse |
| CCM Electronic Engineering | 6400 | Sønderborg |
| Celltech A/S | 3500 | Værløse |
| Chemo Electric A/S | 2765 | Smørum |
| Comadan A/S | 8940 | Randers SV |
| ComSystem A/S | 3490 | Kvistgård |
| Condair A/S | 8680 | Ry |
| CORE-emt A/S | 9600 | Aars |
| CORNATOR A/S | 8800 | Viborg |
| Coromatic A/S | 4000 | Roskilde |
| Cp Sourcing ApS | 7870 | Roslev |
| Craneteam ApS | 8670 | Låsby |
| Cre8tek Denmark ApS | 9800 | Hjørring |
