Rosendo Mercado Ruiz (born 23 February 1954, Madrid, Spain) is a Spanish rock singer and songwriter.

His family was from Bolaños de Calatrava, in the province of Ciudad Real, but he was raised in Carabanchel, where he still resides (as of 2005).

In 1974 Rosendo discovered Rory Gallagher's music, who became one of his main influences, together with other bands such as Jethro Tull, Canned Heat, Cream, Deep Purple and Black Sabbath.

Chiqui Mariscal (bass player) and Ramiro Penas (drums) also left Ñu to join him in Leño.

Rock del Manzanares, which included two Leño's songs: Este Madrid and Aprendiendo a escuchar.

Chiqui Mariscal left the band in the middle of the recording sessions, and he was substituted by Tony Urbano; the disc sleeve portrays this fact.

Despite its poor sound quality, the disc made it quite well at the shops, granting great success to the band.

At the end of the Rock the una noche de verano tour, in the fall of 1983, and when they were at their best and most successful moment, Leño members decided to split off.

Rosendo's first solo disc (Loco por incordiar) was pushed back until 1985, due to problems with his former label, Zafiro (to which Chapa Discos belonged).

It marked the moment of greatest commercial success in his career, thanks to songs like Agradecido, Pan de higo or Loco por incordiar.

After that disc two of his musicians left, namely the keyboard player Gustavo Di Nóbile and the drummer Miguel Ángel Jiménez.

The first disc of this stage is A tientas y barrancas (1998), followed in 1999 by Siempre hay una historia... en directo, which he recorded live in the yard of the Carabanchel prison.