In 1991, Dario Frigo third of the Italian road championship of juniors. From 1995 to 2005 he was at various professional teams under contract. His most notable victories were Paris-Nice in 2001, the Tour de Romandie in 2001 and 2002, the Championship of Zurich in 2002. 2003 he won the Setmana Catalana de Ciclisme.
Four times took Frigo at the Giro d' Italia in part, in 2003 he won the 18th stage and was seventh overall, in the same year he rode the Vuelta a España. Three times -1997, 2002 and 2005 - he started at the Tour de France. For his participation in 2002 he won the 17th stage and was ranked 25 in the overall standings. He was arrested during his Tour participation after the tenth stage of the French police in 2005.
On 13 July 2005 Frigo was arrested in Courchevel after the banned hormone EPO was found in the car of his wife. As early as 2001 there had been an investigation against him for a doping scandal at the Giro d' Italia in 2001 and he was punished with a heavy fine. In April 2009 he and his wife were each sentenced to three months imprisonment on probation after she challenged the original ruling in 2005 -. Periods of six months ' probation plus a fine of 8757 euros - had appealed Frigo described himself as a "victim of the system of systematic doping " in his former team.