Ross Murdoch was sent the letter by a five-year-old boy earlier this month after winning two medals in the pool.
The swimmer received it after it was delivered to his parents' home in West Dunbartonshire despite the envelope being addressed simply to "Ross Murdoch, Commonwealth Champion, Balloch".
The 20-year-old has now appealed to his Twitter followers to help him trace the youngster called Brian to show him where he trains.
The gold medal winner wrote on the social media site today: "RT&help me find 5yo Brian who sent me this amazing letter! I'd love to meet him and show him around where I train :-)".
He previously thanked Royal Mail for ensuring the letter reached him.
On August 11 he wrote: "Parents received some fan mail today. Great @RoyalMail for getting it to the proper destination! #Cute #GoodJob"
Murdoch secured a gold medal in the 200m breaststroke which he later added to with a bronze in the 100m breaststroke.