They replace Redrow Homes.
The deal said to be worth a substantial 6 figure sum will see the company on the front of the new shirts that are due for sale before the end of July.
Speaking at the press conference today CDL Managing Director Matt Burge said
"We think Cardiff's time has come - it's a fantastic European city and with its size and resources, deserves to have a Premiership side.
"There will be many benefits of living and working in a Premiership city and we are fortunate to be in a position to provide the financial support to help with Cardiff's drive to the Premiership. We intend to be a very active partner, not just a sponsor."