| Roles | Competed in Olympic Games |
|---|---|
| Sex | Male |
| Full name | Onni Olavi•Kasslin |
| Used name | Onni•Kasslin |
| Nick/petnames | Onkka |
| Born | 27 February 1927 in Vantaa, Uusimaa (FIN) |
| Died | 9 August 2003 in Helsinki, Uusimaa (FIN) |
| Measurements | 176 cm / 78-82 kg |
| NOC | Finland |
| Games | Discipline (Sport) / Event | NOC / Team | Pos | Medal | As | |
|---|---|---|---|---|---|---|
| 1948 Summer Olympics | Cycling Track (Cycling) | FIN |
Onni Kasslin | |||
| 1,000 metres Time Trial, Men (Olympic) | 10 | |||||
| Team Pursuit, 4,000 metres, Men (Olympic) | Finland | 1 h8 r2/5 | ||||
| 1952 Summer Olympics | Cycling Track (Cycling) | FIN |
Onni Kasslin | |||
| 1,000 metres Time Trial, Men (Olympic) | 14 |