Атлетико Мадрид Б

The club was founded in 1964 as Reyfra Atlético O.J.E. when CD Reyfra (1963–64) and CA Getafe merged. In 1970 it absorbed Aviaco Madrileño CF, which was established in 1967 when Madrileño CF (1956–67) and AD Aviaco merged, became affiliated with Atlético Madrid and in 1970 changed its name to Atlético Madrileño Club de Fútbol.

In 1991, the club changed the name to Atlético Madrid B for the 1991–92 season. Having already played from 1980 to 1986 in Segunda División, the reserves fluctuated between that level and Segunda División B – created in 1977 as the new third division – in the following decades. In the 1998–99 season, the team (which featured Rubén Baraja, future Valencia and Spain star in central midfield) finished in second position in the second division, but was ineligible for La Liga promotion – Numancia gained the automatic promotion slot instead. The following year, they were administratively relegated as the first team went down from La Liga, and in 2000–01 they missed out on promotion in the play-offs but would have been ineligible in any case as the seniors failed to achieve the same goal (they went back up a year later).

The entire 2000s were spent in the third level, but several players continued to make the transition to the first team, including the likes of David de Gea, Álvaro Domínguez, Antonio López, Gabi, Mario Suárez, Koke, Ignacio Camacho, Saúl Ñíguez, Thomas Partey and Lucas Hernandez.

In 2020–21, a poor on-field season combined with reorganisation of the league structure meant that the team was relegated not to the fourth tier but the fifth (Tercera División RFEF), having only spent two seasons below the third level since their first few years of existence over 50 years earlier.