 | IGN VVS AS | 914743834 | OSLO |
| I HELMEN UTEMILJØ AS | 926460110 | GRAN |
| IHUGA AS | 911874571 | OSLO |
| IK BYGG AS | 927159295 | NES |
| IKM OCEAN DESIGN AS | 987818638 | SANDNES |
| IKM SAFE CONTROL AS | 976515501 | TVEDESTRAND |
| IKON ARKITEKT & INGENIØR AS | 992869631 | SMØLA |
| IKON NORGE AS | 912678385 | OSLO |
| IKR INGENIØRKONTOR AS | 991326278 | STAVANGER |
| IKT-ELEKTRO AS | 987218452 | OSLO |
| ILF CONSULTING ENGINEERS NORWAY AS | 812667572 | BAMBLE |
| I LIE & SØNNER AS | 945786728 | SØR-AURDAL |
| IMC DIVING AS | 932624036 | BERGEN |
| IMPERIUM SUMMA AS | 926597922 | FÆRDER |
| IMPLENIA NORGE AS | 980332977 | BÆRUM |
| IMTAS HARSTAD AS | 920900305 | HARSTAD |
| IMTAS PROSJEKT AS | 987309113 | RANA |
| IN BY AS | 858261082 | OSLO |
| INCENDIUM CONSULT AS | 815978102 | DRAMMEN |
| INCUBE AS | 999114954 | OSLO |
| INDERDAL ELEKTRO AS | 912211800 | STEINKJER |
| INDERGÅRD BAD AS | 989582070 | ORKLAND |
| INDIAN BYGG AS | 979923953 | LILLESTRØM |
| INDIGO ARKITEKTER AS | 988579165 | BÆRUM |
| INDIRA AS | 912270440 | NARVIK |
| INDRE AGDER TRANSPORT AS | 886471432 | EVJE OG HORNNES |
| INDRE ØSTFOLD BYGG AS | 921571399 | INDRE ØSTFOLD |
| INDUSTRIRØRLEGGERN AS | 911972433 | SØNDRE LAND |
| INFLUIT AS | 929303822 | ØYGARDEN |
| INFRAKON AS | 925918946 | RANA |
| INFRASTRUKT AS | 911585308 | KONGSVINGER |
| INFRATEK NORGE AS | 984277032 | OSLO |
| INGARD LANGSHOLDT AS | 932106450 | SARPSBORG |
| INGAR GJESMOE BYGG- OG BRANNTEKNIKK -RÅDGIVING | 990449309 | DRAMMEN |
| ING. ASBJØRN DANIELSEN AS | 924300094 | BERGEN |
| ING. ATIF AKRAM | 994739778 | MOSS |
| INGEBO MASKIN AS | 927979055 | ØVRE EIKER |
| INGE BYBERG AS | 916338651 | EIGERSUND |
| ING. EGIL CHRISTIANSEN | 991762264 | BÆRUM |
| ING. EGIL CHRISTIANSEN AS | 932139677 | BÆRUM |
| INGE HAUGAN BYGG AS | 987038489 | TRONDHEIM |
| INGE JENSEN MASKIN AS | 988412597 | SORTLAND |
| INGEMANN AS | 995696770 | SULDAL |
| INGENIØR AARLAND AS | 979971044 | BERGEN |
| INGENIØR ANN-THERES LØCHEN | 999548903 | FREDRIKSTAD |
| INGENIØR BYGG AS | 931773194 | STANGE |
| INGENIØRFIRMA BIG AS | 976721144 | FREDRIKSTAD |
| INGENIØRFIRMAET L S SOLLAND AS | 918160922 | STAVANGER |
| INGENIØRFIRMAET R. TORGERSEN AS | 987396245 | ASKØY |
| INGENIØRFIRMAET SVENDSEN & CO AS | 975950530 | SARPSBORG |