The Lausanne-based organisation has ruled United must pay 195,000 euros to Argentina side Velez Sarsfield in respect of the development of the striker who moved to Tannadice in 2009.
Dundee United believed the player was a free agent and no transfer fee would be involved but a FIFA tribunal later ordered they pay 400,000 euros to the club where the 26-year-old had graduated through the youth ranks before making two first-team appearances in 2008.
That ruling was later reduced to 230,000 euros on appeal, an amount which the Scottish Premiership side again contested, resulting in CAS cutting it by a further 35,000 euros.
In a statement on their official website, the club said: "Dundee United note with disappointment the decision of CAS to only partially uphold our appeal and award 195,000 Euros in respect of training compensation to Velez Sarsfield in respect of Damian Casalinouvo.
"We are encouraged that the original claim has been reduced and will now consider the decision fully before making any further comment."
Casalinuovo, who scored seven goals in 25 games for Dundee United, had a brief spell on loan at Raith Rovers, scoring twice in three matches, before leaving Tannadice for Hamilton in 2010, where he drew a blank in 19 appearances for the Accies.
After a brief spell back at Raith Rovers last year, he called time on his professional career due to a back injury before returning home to his native Argentina.