Her first full marathon race was the 2003 Chicago Marathon, where she finished twelfth in 2:31:34. She finished fifth over 10,000 metres at the 2003 Pan American Games. She won the Bolder Boulder 10K race in 2004, and also won the Guadalajara Half Marathon that year, in the first of three consecutive wins. In 2005, she finished eleventh in the marathon at the World Championships in a personal best time of 2:26:50, and sixth at the 2005 IAAF World Half Marathon Championships. In 2006, she finished fourth at the Chicago Marathon in a new Mexican record time of 2:22:59. In the 2007 Boston Marathon she came in third (2:30:16). At the 2007 Athletics World Championships in Osaka, Japan she finished in 15th position, thus being the best female Latin American participant (2:35:17). The old record belonged to Adriana Fernández.