| Cadskolen A/S | 9000 | Aalborg |
| Carl Ras A/S | 2730 | Herlev |
| Carlog System | 9440 | Aabybro |
| CB Group | 5000 | Odense C |
| CB Svendsen A/S | 3500 | Værløse |
| Ceetec A/S | 5500 | Middelfart |
| Celsa Steel Service A/S | 3650 | Ølstykke |
| Centrum Pæle A/S | 7100 | Vejle |
| CEPELO A/S | 9200 | Aalborg SV |
| CERTEX Danmark A/S | 6500 | Vojens |
| CG Jensen A/S | 2600 | Glostrup |
| Charles Christensen A/S | 2730 | Herlev |
| City Group Brandsikring A/S | 5500 | Middelfart |
| City Group Overfladebehandling A/S | 5500 | Middelfart |
| CJ A/S | 7000 | Fredericia |
| CLT Denmark A/S | 2740 | Skovlunde |
| CLT Factory ApS | 8240 | Risskov |
| Colas Danmark A/S | 2600 | Glostrup |
| CONFAC A/S | 8940 | Randers SV |
| Constructia ApS | 8464 | Galten |
| Coromatic A/S | 4000 | Roskilde |
| Crafted Furniture ApS | 1736 | København V |
| CRH Concrete A/S | 4130 | Viby Sjælland |
| CG Jensen A/S | 2600 | Glostrup |
| CREO ARKITEKTER A/S | 5000 | Odense |