 | NILSEN VVS AS | 913509811 | ASKØY |
| NILS INGE TJELTA AS | 863233062 | SOLA |
| NILS JR FREY | 970326170 | KRISTIANSUND |
| NILS KALDAHL ANLEGG & TRANSPORT AS | 886833172 | NAMSOS |
| NILS LØFF AS | 983976956 | KONGSBERG |
| NILS OMA MASKIN AS | 920734170 | TIME |
| NILS REIME MASKIN AS | 987709111 | HÅ |
| NILSSON AS | 983494226 | BODØ |
| NILSSON HARAS AS | 919546646 | SORTLAND |
| NILSSON MO AS | 986444327 | RANA |
| NILS TORE AAMODT | 970156097 | HAMAR |
| NIMBUS FIBER AS | 895204862 | OSLO |
| NINO RØRLEGGER AS | 923843175 | OSLO |
| NIPEDAL TAK OG MEMBRAN AS | 932481588 | VENNESLA |
| NIRO BYGG AS | 927328852 | VERDAL |
| NITEK AS | 983437273 | ALTA |
| NITREX AS | 991853529 | SALTDAL |
| NITTEDAL RØRLEGGERBEDRIFT AS | 916998767 | LILLESTRØM |
| NIVÅBYGG AS | 919290757 | OSLO |
| NJÆRHEIM RØR AS | 996324958 | SANDNES |
| NJS BYGGSERVICE AS | 916538235 | RINGERIKE |
| NK PRO BYGG AS | 898632032 | KRISTIANSUND |
| NKTR HOLDING AS | 922529116 | MODUM |
| NL ARKITEKTUR AS | 931120174 | RINGERIKE |
| NLI ELEKTROSYSTEMER AS | 989042335 | TØNSBERG |
| NLI ENGINEERING AS | 887994722 | TØNSBERG |
| NM RØR AS | 996798011 | OSLO |
| NMS EIENDOM BERGEN AS | 922179611 | BERGEN |
| NMT NORDMARK MASKIN & TRANSPORT AS | 948469049 | HARSTAD |
| NOA VVS AS | 915448941 | STORD |
| NOBEL RØR INSTALLASJON AS | 992139633 | VÅGAN |
| NOBI BYGG OG BETONG AS | 931491865 | VOSS |
| NO BYGG AS | 814968502 | SKIEN |
| NODDELAND BYGG | 984607245 | FROLAND |
| NODE RÅDGIVENDE INGENIØRER AS | 919853557 | BERGEN |
| NOIR RØRLEGGERSERVICE AS | 915925421 | OSLO |
| NOKAS TEKNIKK SØR AS | 979276141 | TØNSBERG |
| NØKKEL-FERDIG AS | 995702444 | HOLMESTRAND |
| NØKLAND RØRLEGGERSERVICE AS | 915514758 | LYNGDAL |
| NØKLEBY EIENDOMSUTVIKLING AS | 919233400 | FREDRIKSTAD |
| NOLA HUS AS | 998501288 | TRONDHEIM |
| NOPEK ELEKTRO AS | 968958356 | LIER |
| NORACTOR AS | 930846589 | LILLESTRØM |
| NOR AGGREGATES AS | 915058493 | VINDAFJORD |
| NORALF REILSTAD | 970386203 | STAVANGER |
| NORAVIND BYGG AS | 928823695 | ØYGARDEN |
| NORAX TYNSET AS | 984697082 | TYNSET |
| NORBECK ENT AS | 994390902 | OPPDAL |
| NORBECK ENTREPRENØR AS | 933455211 | OPPDAL |
| NORBECK RØR AS | 929648870 | ULLENSAKER |