As an amateur, he won a bronze medal at the 2003 Pan American Games and competed at the 2004 Olympics, both in the heavyweight division.
In international fights he lost twice to Kertson Manswell in 2003 but beat him in 2004 to qualify for the Olympics.
He sustained his first defeat by a ranked opponent, Kevin Johnson (boxer), in a May 15, 2009 bout.
It became clear early in the fight that Vargas was in over his head, being dropped in the 3rd—giving Johnson a massive lead—and again in the 5th round.
Bloody and bruised during the latter, Vargas looked like a beaten man, and it was evident that the end was near.