| Competition: | Primera B Nacional |
| Season: | 2009–10 |
| Winners: | Olimpo (3rd divisional title) |
| Promoted: | Olimpo Quilmes All Boys |
| Relegated: | Platense Sportivo Italiano |
| League Topscorer: | Leandro Armani (19 goals) |
| Prevseason: | 2008–09 |
| Nextseason: | 2010–11 |
The 2009–10 Argentine Primera B Nacional was the 24th season of second division professional of football in Argentina. A total of 20 teams competed; the champion and runner-up were promoted to Argentine Primera División.
| Club | City | Stadium | |
|---|---|---|---|
| Aldosivi | Mar del Plata | José María Minella | |
| All Boys | Floresta | Islas Malvinas | |
| Atlético de Rafaela | Rafaela | Nuevo Monumental | |
| Córdoba | El Gigante de Alberdi | ||
| Corrientes | José Antonio Romero Feris | ||
| Comodoro Rivadavia | Municipal de Comodoro Rivadavia | ||
| Florencio Varela | Norberto "Tito" Tomaghello | ||
| Parque San Martín | José Manuel Moreno | ||
| Ferro Carril Oeste | Caballito | Arq. Ricardo Etcheverry | |
| Gimnasia y Esgrima | San Salvador de Jujuy | 23 de Agosto | |
| Independiente Rivadavia | Mendoza | Bautista Gargantini | |
| Instituto | Córdoba | Presidente Perón | |
| Olimpo | Bahía Blanca | Roberto Natalio Carminatti | |
| Platense | Florida | Ciudad de Vicente López | |
| Quilmes | Quilmes | Centenario | |
| San Martín | San Juan | Ing. Hilario Sánchez | |
| San Martín | San Miguel de Tucumán | La Ciudadela | |
| Sportivo Italiano | Ciudad Evita | Republica de Italia | |
| Tiro Federal | Rosario | Fortín de Ludueña | |
| Unión | Santa Fe | 15 de Abril |
The 3rd and 4th placed of the table played with the 18th and the 17th placed of the Relegation Table of 2009–10 Primera División.|-!colspan="5"|Promotion playoff 1|-!colspan="5"|Promotion playoff 2|-|}
| width=28 | width=185 | Team | width=50 | width=50 | width=50 | width=50 | width=50 | width=50 | Situation | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Atlético de Rafaela | 53 | 62 | 53 | 178 | 114 | Indirect | ||||||||||
| 2 | 56 | 62 | 57 | 175 | 114 | Indirect | |||||||||||
| 3 | San Martín (T) | 66 | — | 50 | 116 | 76 | Indirect | ||||||||||
| 4 | Quilmes | 55 | 51 | 64 | 170 | 114 | Direct | ||||||||||
| 5 | All Boys | — | 50 | 63 | 113 | 76 | Direct | ||||||||||
| 6 | Olimpo | — | 40 | 71 | 111 | 76 | Direct | ||||||||||
| 7 | Gimnasia y Esgrima (J) | — | — | 54 | 54 | 38 | Indirect | ||||||||||
| 8 | Instituto | 43 | 59 | 60 | 162 | 114 | Indirect | ||||||||||
| 9 | San Martín (SJ) | — | 49 | 58 | 107 | 76 | Indirect | ||||||||||
| 10 | Unión | 56 | 49 | 53 | 158 | 114 | Direct | ||||||||||
| 11 | Ferro Carril Oeste | 51 | 52 | 48 | 151 | 114 | Direct | ||||||||||
| 12 | Tiro Federal | 54 | 50 | 44 | 148 | 114 | Indirect | ||||||||||
| 13 | Aldosivi | 48 | 57 | 48 | 147 | 114 | Indirect | ||||||||||
| 14 | — | — | 48 | 48 | 38 | Indirect | |||||||||||
| 15 | Defensa y Justicia | 43 | 49 | 52 | 144 | 114 | Direct | ||||||||||
| 16 | Independiente Rivadavia | 47 | 50 | 47 | 144 | 114 | Indirect | ||||||||||
| 17 | Deportivo Merlo | — | — | 46 | 46 | 38 | Relegation Playoff Matches | Direct | |||||||||
| 18 | 51 | 36 | 43 | 130 | 114 | Relegation Playoff Matches | Indirect | ||||||||||
| 19 | Platense | 41 | 37 | 49 | 127 | 114 | Primera B Metropolitana | Direct | |||||||||
| 20 | Sportivo Italiano | — | — | 22 | 22 | 38 | Primera B Metropolitana | Direct |
The bottom two teams of this table face relegation regardless of their affiliation status. Apart from them, the bottom teams of each affiliation face promotion/relegation playoffs against Torneo Argentino A and Primera B Metropolitana's "Reducido" (reduced tournaments) champions. The Reducidos are played after those leagues' champions are known.
Updated as of games played on June 18, 2010.
Source:[1]
|-!colspan="5"|Relegation/promotion playoff 1 (Direct affiliation vs. Primera B Metropolitana)|-!colspan="5"|Relegation/promotion playoff 2 (Indirect affiliation vs. Torneo Argentino A)