Alejandro Manuel Cárdenas Robles (born October 4, 1974) is a retired track & field athlete from Mexico.
Cárdenas also participated in 1999 at the IAAF World Indoor Championships in the 400 m dash, in which he earned a bronze medal.
That same year he also participated in the World Championships in Athletics, where he ran a personal record of 44.31 s, which earned him third place.
Cárdenas played an active role in the 2000 Summer Olympics, in the 400 m dash, running 46.14 s in the First Round, and 45.66 in the semifinals, where he did not advance.
In 2005 Cárdenas participated in the World Championships, in Helsinki, Finland, being eliminated in the first round with a time of 46.73 s.