| Competition: | Serie B TIM |
| Season: | 2004–05 |
| Promoted: | Empoli (1st title) Ascoli Treviso |
| Relegated: | Genoa Perugia Salernitana Venezia (to C2) |
| League Topscorer: | Gionatha Spinesi (22 goals) |
| Matches: | 462 |
| Total Goals: | 1098 |
| Prevseason: | 2003–04 |
| Nextseason: | 2005–06 |
The 2004–05 Serie B is the 73rd season since its establishment in 1929. It is the second highest football league in Italy.
Arezzo, Catanzaro, Cesena and Crotone had been promoted from Serie C, while Perugia, Modena, and Empoli had been relegated from Serie A, and Ancona had lost their national professional licence.
| Team | President | Manager | Kit manufacturer | Shirt sponsor | |
|---|---|---|---|---|---|
| AlbinoLeffe |  Gianfranco Andreoletti | Elio Gustinetti | Legea | SCAME | |
| Arezzo | Piero Mancini | Pasquale Marino | Legea | Banca Etruria | |
| Ascoli | Roberto Benigni | Marco Giampaolo and Massimo Silva | Uhlsport | Carisap | |
| Bari | Vincenzo Matarrese | Guido Carboni | Lotto | Pasta Ambra | |
| Catania | Antonino Pulvirenti | Nedo Sonetti | Galex | SP Energia Siciliana, Regione Siciliana | |
| Catanzaro | Claudio Parente | Bruno Bolchi | Asics | Catanzaro città tra due mari, Caffè Guglielmo | |
| Cesena | Giorgio Lugaresi | Fabrizio Castori | Lotto | Solo Affitti | |
| Crotone | Raffaele Vrenna | Gian Piero Gasperini | Devis | Sovreco (H)/Frais Monde (A) | |
| Empoli | Fabrizio Corsi | Mario Somma | Asics | Computer Gross | |
| Genoa | Enrico Preziosi | Serse Cosmi | Asics | Costa Cruises | |
| Hellas Verona | Giambattista Pastorello | Massimo Ficcadenti | Legea | Clerman | |
| Modena | Romano Amadei | Stefano Pioli | Erreà | Immergas, Alberti & Tagliazucchi | |
| Perugia | Alessandro Gaucci | Stefano Colantuono | Galex | Mobili Paolo | |
| Pescara | Dante Paterna | Giovanni Simonelli | Ennedue | Eurovision TV | |
| Piacenza | Fabrizio Garilli | Giuseppe Iachini | Lotto | UNICEF | |
| Salernitana | Aniello Aliberti | Angelo Gregucci | Devis | Centrale del Latte di Salerno/Caffè Motta | |
| Ternana | Luigi Agarini | Claudio Tobia | Erreà | None | |
| Torino | Attilio Romero | Renato Zaccarelli | Asics | Bavaria | |
| Treviso | Ettore Setten | Giuseppe Pillon | Lotto | Segafredo, Provincia di Treviso | |
| Triestina | Amilcare Berti | Attilio Tesser | Asics | Bossini | |
| Venezia | Francesco Dal Cin | Andrea Manzo | Sportika | Boscolo Tours | |
| Vicenza |  Sergio Cassingena | Maurizio Viscidi | Biemme | Caffè Vero, Supermercati SISA |
Following the long-standing consequences of the “Caso Catania”, the league included 22 teams, while promotions decreased to three spots.
Promotion playoffs were also introduced.
(later became a relegation play-off)
Torino Calcio promoted to Serie A, but later it went bankrupt and it was restored in 2005–06 Serie B by the Lodo Petrucci. Perugia Calcio also went bankrupt and it was restored in 2005–06 Serie C1 by the Lodo Petrucci.
This promotion play-off consequently became a relegation play-off.
(later annulled)
Vicenza Calcio was lucky because its relegation was annulled following the Caso Genoa.