Chelsea have been seeking damages from Mutu in relation to a breach of contract for more than two years, after he signed for Juve in January 2005.
The Blues had sacked Mutu three months prior after he tested positive for cocaine and have been chasing compensation every since he signed for Juve.
Mutu spent a single season with Juve but FIFA's dispute resolution chamber have now ruled that the Old Lady are liable for close to £17m in damages, with Livorno also involved after they held the Romanian striker's registration during that year.
Both clubs still have a right of appeal to the Court of Arbitration for Sport, with a timeline yet to be placed on that process.
The 34-year-old has since played for Fiorentina and Cesena in Italy, before switching to French side Ajaccio last summer.