| C-TV Technology A/S | 9000 | Aalborg |
| Cadskolen A/S | 9000 | Aalborg |
| Carl Ras A/S | 2730 | Herlev |
| Carlo Gavazzi Handel A/S | 8370 | Hadsten |
| Carlog System | 9440 | Aabybro |
| CB Group | 5000 | Odense C |
| CB Svendsen A/S | 3500 | Værløse |
| Ceetec A/S | 5500 | Middelfart |
| CEPELO A/S | 9200 | Aalborg SV |
| CERTEX Danmark A/S | 6500 | Vojens |
| CESCO A/S | 6690 | Gørding |
| Cetonia A/S | 8850 | Bjerringbro |
| Charles Christensen A/S | 2730 | Herlev |
| City Group Brandsikring A/S | 5500 | Middelfart |
| City Group Overfladebehandling A/S | 5500 | Middelfart |
| CitySystem A/S | 3200 | Helsinge |
| CJ A/S | 7000 | Fredericia |
| CK Produktion | 7190 | Billund |
| CLT Factory ApS | 8240 | Risskov |
| Colas Danmark A/S | 2600 | Glostrup |
| Colloc ApS | 8381 | Tilst |
| ComSystem A/S | 3490 | Kvistgård |
| Condair A/S | 8680 | Ry |
| Copenhagen Hardwood ApS | 3670 | Veksø Sjælland |
| Coromatic A/S | 4000 | Roskilde |
| Cre8tek Denmark ApS | 9800 | Hjørring |
| CRH Concrete A/S | 4130 | Viby Sjælland |
| CSK Stålindustri A/S | 7700 | Thisted |