Head coach Matt Sherratt says he is delighted to keep Lee-Lo for another season.
“He has been one of the leading centres in European rugby for a number of years and showed he can still perform at a consistently high level throughout last season,” said Sherratt.
“He has been there and done it and is a great experienced, senior presence for our young players both on and off the pitch.
“It is no coincidence that the likes of Ben Thomas and Mason Grady have developed so well with Rey often next to them.”
Cardiff have also signed former Newcastle duo Ryan Jennings and Iwan Stephens, ex-Bristol pair Callum Sheedy and Dan Thomas, props Ed Byrne and Danny Southworth and wing Gabriel Hamer-Webb.
Grady, Corey Domachowski, Liam Belcher, Keiron Assiratti, Cameron Winnett, Alex Mann, Mackenzie Martin, Evan Lloyd, Harri Millard, James Botham, Jacob Beetham, Alun Lawrence and Dafydd Hughes are among the players who have committed their futures at the Arms Park.
Departing Cardiff players include Tomos Williams, Rhys Carre, Owen Lane, Ciaran Parker, Aled Summerhill, Arwel Robson Max Clark, Gonzalo Bertranou, Matthew Aubrey and Willis Halaholo.