|World Championships (SC)|
|2006 Shanghai||4 x 200 m freestyle|
|2008 Manchester||4×200 m freestyle|
|European Aquatics Championships (LC)|
|2006 Budapest||4x200m Freestyle|
|2008 Eindhoven||4×200 m freestyle|
|2005 Izmir||4×200 m freestyle|
|2009 Belgrade||4×100 m freestyle|
|2009 Belgrade||4×100 m medley|
|2007 Bangkok||4×200 m freestyle|
Cassio won several medals mainly as a member of the Italian 4 x 200 m freestyle relay. He participated for Italy in the 2008 Summer Olympics.
- Evans, Hilary; Gjerde, Arild; Heijmans, Jeroen; Mallon, Bill. "Nicola Cassio". Olympics at Sports-Reference.com. Sports Reference LLC.
- Nicola Cassio on Italian Swimming Federation's website (in Italian)