| Roles | Competed in Olympic Games | |
|---|---|---|
| Sex | Male | |
| Full name | Niels Marius•Nielsen | |
| Used name | Niels•Nielsen | |
| Born | 5 October 1883 in Oslo, Oslo |  NOR |
| Died | 9 February 1961 (aged 77 years 4 months 4 days) in Bærum, Viken | NOR |
| Affiliations | KNS — Oslo, Oslo | NOR |
| NOC | Norway | NOR |
| Medals | OG |
| Gold | 0 |
| Silver | 1 |
| Bronze | 0 |
| Total | 1 |
| Games | Discipline (Sport) / Event | NOC / Team | Pos | Medal | As | |
|---|---|---|---|---|---|---|
| 1920 Summer Olympics | Sailing | NOR |
Niels Nielsen | |||
| 7 metres, Open (Olympic) | Fornebo | 2 | Silver |
