| Roles | Non-starter |
|---|---|
| Sex | Male |
| Full name | Dethloff•Siem |
| Used name | Dethloff•Siem |
| Born | 20 January 1905 in Amsterdam, Noord-Holland (NED) |
| Died | 14 November 1973 (aged 68 years 9 months 25 days) |
| NOC |  Netherlands |
| Games | Discipline (Sport) / Event | NOC / Team | Pos | Medal | As | |
|---|---|---|---|---|---|---|
| 1948 Summer Olympics | Equestrian Jumping (Equestrian) | NED |
Dethloff Siem | |||
| Individual, Open (Olympic) | ||||||
| Team, Open (Olympic) | Netherlands |
