 Santos defended this championship on four occasions, against Mehrdud Takaloo (in a fight where he won the World Boxing Union Light middleweight championship), Fulgencio Zúñiga, Michael Lerma and Antonio Margarito before losing it to Sergiy Dzindziruk by unanimous decision in a fight that took place on December 3, 2005.On July 11, 2008, Santos won his third professional championship, knocking out Joachim Alcine in six rounds to win the World Boxing Association's light middleweight title.Santos was raised in a family where boxing was a common profession, with his father Paquito Santos being a trainer and his brother Edgardo Santos being a former professional boxer.