| Ces I AS | Bodø | 2023 |
| Cest AS | Voss | 2001 |
| Cfo Invest AS | Stavanger | 2020 |
| Cfrgyn AS | Os | 2020 |
| Chalma Holding AS | Kristiansand S | 2016 |
| Chambers Bay AS | Norheimsund | 2017 |
| Champion Idrettsmassasje & Trening AS | Grålum | 2025 |
| Change Forever AS | Skreia | 2017 |
| Charlotte Bjørk Ingul AS | Trondheim | 2005 |
| Charlotte Gravrok AS | Charlottenlund | 2026 |
| Charlottenlund Legesenter Da | Charlottenlund | 1986 |
| Charlottes Fotterapi AS | Søgne | 2025 |
| Checkpoint Medisinske AS | Kristiansand S | 2025 |
| Cheema Holding AS | Sem | 2017 |
| Chel AS | Oslo | 2023 |
| Cherry Enterprises AS | Jessheim | 2024 |
| Chi Huset Ans | Drammen | 1999 |
| Chiasma AS | Hamar | 2013 |
| Chikara AS | Trondheim | 2015 |
| Chiron Helse AS | Godøya | 2015 |
| Christensen Urologi AS | Kristiansand S | 2021 |
| Christian Busch AS | Bergen | 2010 |
| Christian Fredrik Kroepelien AS | Snarøya | 2022 |
| Christian Hellum AS | Oslo | 2020 |
| Christian J Mohn AS | Paradis | 1910 |
| Christian Smedsrud AS | Tønsberg | 2015 |
| Christian Øiom Holding AS | Oslo | 2021 |
| Christian Øiom Operations AS | Oslo | 2024 |
| Christiania Healthcare AS | Oslo | 2013 |
| Christiania Nevrologipraksis AS | Nesodden | 2017 |
| Christiania Nevropsykologi AS | Oslo | 2016 |
| Christiania Privatklinikk AS | Oslo | 2023 |
| Christiansen Urologi AS | Hamar | 2017 |
| Christianslund Legekontor Da | Fredrikstad | 2011 |
| Christina Jessica AS | Tolvsrød | 2023 |
| Christine Hamnvik AS | Asker | 2025 |
| Christins Fotterapi AS | Moss | 2016 |
| Christoffersen Helse AS | Råholt | 2023 |
| Christoffersen Invest AS | Råholt | 2023 |
| Christophersen Madsen Holding AS | Oslo | 2025 |
| Chryso Holding AS | Stord | 2024 |
| CHS Fysioterapi AS | Løvenstad | 2024 |
| Ciaj HN AS | Stavanger | 2018 |
| Ciere Klinikken AS | Frekhaug | 2012 |
| Cilaris AS | Stord | 2020 |
| Ciljan AS | Klæbu | 1980 |
| CINELL1 AS | Oslo | 2019 |
| Cinus Hørsel AS | Førresfjorden | 2013 |
| City Legesenter AS | Drammen | 2015 |
| City Nord Tannhelse AS | Bodø | 2015 |
| City Syd Klinikken AS | Moss | 2016 |
| City-Klinikken AS | Oslo | 2012 |
| City-Med AS | Arendal | 2014 |
| CK Dermatological Solutions and Services AS | Porsgrunn | 2019 |
| CK Rådgivning AS | Revetal | 2026 |
| Claria AS | Bøverbru | 2021 |
| Clarsen Sports Medicine Consulting AS | Søreidgrend | 2024 |
| Clausen Fysioterapi Da | Kleppestø | 2022 |
| Clavicula AS | Tromsø | 2015 |
| Cle Wellness Consulting AS | Oslo | 2026 |
| Clean Skin AS | Gamle Fredrikstad | 2025 |
| Clear Ink AS | Bergen | 2015 |
| Clear Tannlegesenter AS | Oslo | 2019 |
| Clem Omsorg AS | Gjøvik | 2020 |
| CLH Holding AS | Porsgrunn | 2018 |
| Clinic 112 Varda Baig AS | Lørenskog | 2013 |
| Clinic 55 AS | Haugesund | 2025 |
| Clinic Medica Da | Asker | 2004 |
| Clinic Vest AS | Oslo | 2022 |
| Clinica AS | Oslo | 2019 |
| Cliniccare Norge AS | Oslo | 2022 |
| Clinicus AS | Oslo | 2020 |
| Clinique Bellevue AS | Stavanger | 2016 |
| Clinique Lovisa AS | Kristiansand S | 2001 |
| CME2 AS | Drøbak | 2016 |
| Cmedical AS | Oslo | 2013 |
| Cmedical Group AS | Oslo | 2017 |
| Cmedical Ivf-Klinikken Oslo AS | Oslo | 2010 |
| Cmedical Moelv AS | Moelv | 2020 |
| CMP Helse AS | Oslo | 2025 |
| Cmud AS | Kristiansund N | 2009 |
| Cmørk AS | Oslo | 2006 |
| Cn-Manuellterapi AS | Oslo | 2013 |
| Cni AS | Billingstad | 2017 |
| Cochlea Drift AS | Asker | 2024 |
| Coco Bello Holding AS | Tromsø | 2025 |
| Coco Bello Medical AS | Tromsø | 2025 |
| Cogito Manuell Medisin AS | Oslo | 2012 |
| Cognitio AS | Oslo | 2020 |
| Cojeno AS | Oslo | 2013 |
| Collective Minds Radiology AS | Oslo | 2019 |
| Collumcapite AS | Ålesund | 2020 |
| Colonklinikken Tveitan AS | Oslo | 2019 |
| Colosseum Dental Group Holding AS | Oslo | 2017 |
| Colosseum Faust AS | Moss | 2019 |
| Colosseum Øyelegesenter AS | Oslo | 2002 |
| Colosseumklinikken Allmennseksjonen AS | Oslo | 2001 |
| Colosseumklinikken AS | Oslo | 1996 |
| Colosseumklinikken Medisinske Senter AS | Oslo | 2014 |
| Colship AS | Kongsberg | 1988 |