| C & L Turned Parts A/S | 8930 | Randers NØ |
| C.C.JENSEN A/S | 5700 | Svendborg |
| C.K. Produktion | 7190 | Billund |
| Cadskolen A/S | 9000 | Aalborg |
| CALDAN Conveyor A/S | 8464 | Galten |
| Camozzi Automation ApS | 4000 | Roskilde |
| Carl Stahl A/S | 7000 | Fredericia |
| Carl Zeiss A/S | 3460 | Birkerød |
| Carlo Gavazzi Handel A/S | 8370 | Hadsten |
| Carmo A/S | 3060 | Espergærde |
| Carsten Holm A/S | 5750 | Ringe |
| Castolin Scandinavia AB | 422 04 | Hisings Backa |
| CB Svendsen A/S | 3500 | Værløse |
| CCM Electronic Engineering | 6400 | Sønderborg |
| Ceetec A/S | 5500 | Middelfart |
| CERATIZIT Scandinavia AB | 200 39 | Malmö |
| CERTEX Danmark A/S | 6500 | Vojens |
| Cheminor A/S | 8543 | Hornslet |
| CIDAN Machinery | 8300 | Odder |
| CIMCO A/S | 2100 | København Ø |
| Cimpro A/S | 6600 | Vejen |
| City Group Brandsikring A/S | 5500 | Middelfart |
| City Group Overfladebehandling A/S | 5500 | Middelfart |
| CK Deep Drawing | C & K Johansen A/S Denmark | 8700 | Horsens |
| Clean Blast ApS | 5220 | Odense SØ |
| Cleentek A/S | 7100 | Vejle |
| Clip-Lok Simpak ApS | 3450 | Allerød |
| CNC FORCE ApS | 8723 | Løsning |
| CNC Onsite A/S | 7100 | Vejle |
| CNC Products A/S | 8300 | Odder |
| cnc-nordic ApS | 8722 | Hedensted |
| CO4 Maskinfabrik A/S | 8940 | Randers SV |
| Colour Compagniet A/S | 6933 | Kibæk |
| Columbus A/S | 2750 | Ballerup |
| ComSystem A/S | 3490 | Kvistgård |
| Condair A/S | 8680 | Ry |
| Constructor Danmark A/S | 4320 | Lejre |
| Copenhagen Pump | 2650 | Hvidovre |
| Coromatic A/S | 4000 | Roskilde |
| CP ApS | 4130 | Viby Sjælland |
| Cre8tek Denmark ApS | 9800 | Hjørring |
| CNC-TEAM A/S | 8700 | Horsens |