1990–91 Segunda División B
The 1990–91 Segunda División B season was the 14th since its establishment. The first matches of the season were played on 1 September 1990, and the season ended in 23 June 1991 with the promotion play-off final games.
Overview before the season
80 teams joined the league, including four relegated from the 1989–90 Segunda División and 18 promoted from the 1989–90 Tercera División. The composition of the groups was determined by the Royal Spanish Football Federation, attending to geographical criteria.;Relegated from Segunda División:
;Promoted from Tercera División:
- Compostela
- Vetusta
- Gimnástica Torrelavega
- Alavés
- Sant Andreu
- Torrent
- Móstoles
- Palencia
- Los Boliches
- Fuengirola
- Betis Deportivo
- Manacor
- Las Palmas Atlético
- Yeclano
- Extremadura
- Izarra
- Huesca
- Valdepeñas
Group 1
Teams from Asturias, Castile and Leon, Galicia and Madrid.Teams
| Team | Founded | Home city | Stadium |
| Alcalá | 1923 | Alcalá de Henares, Madrid | El Val |
| As Pontes | 1960 | As Pontes, Galicia | O Poboado |
| Atlético Madrileño | 1969 | Madrid, Madrid | Vicente Calderón |
| Real Ávila | 1923 | Ávila, Castile and Leon | Adolfo Suárez |
| Cambados | 1963 | Cambados, Galicia | Burgáns |
| Compostela | 1962 | Santiago de Compostela, Galicia | Santa Isabel |
| Cultural Leonesa | 1923 | León, Castile and Leon | Antonio Amilvia |
| Getafe | 1983 | Getafe, Madrid | Las Margaritas |
| Langreo | 1961 | Langreo, Asturias | Ganzábal |
| Leganés | 1928 | Leganés, Madrid | Luis Rodríguez de Miguel |
| Lugo | 1953 | Lugo, Galicia | Anxo Carro |
| Móstoles | 1955 | Móstoles, Madrid | El Soto |
| Orense | 1952 | Ourense, Galicia | O Couto |
| Palencia | 1975 | Palencia, Castile and León | La Balastera |
| Pegaso | 1962 | Tres Cantos, Madrid | La Foresta |
| Ponferradina | 1922 | Ponferrada, Castile and Leon | Fuentesnuevas |
| Pontevedra | 1941 | Pontevedra, Galicia | Pasarón |
| Real Madrid B | 1930 | Madrid, Madrid | Ciudad Deportiva |
| Sporting Atlético | 1960 | Gijón, Asturias | Mareo |
| Vetusta | 1930 | Oviedo, Asturias | Carlos Tartiere |
League table
Group 2
Teams from Andorra, Aragon, Basque Country, Cantabria, Catalonia, Castile and Leon and Navarre.Teams
| Team | Founded | Home city | Stadium |
| Alavés | 1921 | Vitoria-Gasteiz, Basque Country | Mendizorroza |
| Andorra CF | 1957 | Andorra, Aragon | Juan Antonio Endeiza |
| FC Andorra | 1942 | Andorra la Vella, Andorra | Comunal |
| Barakaldo | 1917 | Barakaldo, Basque Country | Lasesarre |
| Basconia | 1913 | Basauri, Basque Country | Basozelai |
| Binéfar | 1922 | Binéfar, Aragon | El Segalar |
| Deportivo Aragón | 1958 | Zaragoza, Aragon | Ciudad Deportiva del Real Zaragoza |
| Durango | 1919 | Durango, Basque Country | Tabira |
| Gimnástica de Torrelavega | 1907 | Torrelavega, Cantabria | El Malecón |
| Huesca | 1960 | Huesca, Aragon | El Alcoraz |
| Izarra | 1924 | Estella-Lizarra, Navarre | Merkatondoa |
| Lemona | 1923 | Lemoa, Basque Country | Arlonagusia |
| Mirandés | 1927 | Miranda de Ebro, Castile and Leon | Anduva |
| Mollerussa | 1930 | Mollerussa, Catalonia | Municipal Mollerussa |
| Numancia | 1945 | Soria, Castile and León | Los Pajaritos |
| Osasuna Promesas | 1962 | Aranguren, Navarre | Tajonar |
| Racing de Santander | 1913 | Santander, Cantabria | El Sardinero |
| San Sebastián | 1951 | San Sebastián, Basque Country | Atotxa |
| Santurtzi | 1952 | Santurtzi, Basque Country | San Jorge |
| Teruel | 1954 | Teruel, Aragon | Pinilla |