David Zabriskie, born in Salt Lake City on January 12, 1979, is a former American professional road racing cyclist, active from 1999 to 2013. Known for his exceptional time-trialing abilities, he won the United States National Time Trial Championship seven times. His career is marked by significant successes in the Grand Tours, as he is one of the few riders to have won at least one stage in all three major races: the Tour de France, the Giro d'Italia, and the Vuelta a España. Among his most prestigious results is his victory in the prologue of the 2005 Tour de France, a performance that allowed him to wear the yellow jersey as the leader of the general classification. In 2012, Zabriskie testified in the USADA investigation against Lance Armstrong, admitting to the use of doping substances during part of his career, which led to a six-month suspension and the revocation of his results obtained between 2003 and 2006. He retired from professional competition at the end of the 2013 season.