| Competition: | Serie B |
| Season: | 1999–2000 |
| Promoted: | Vicenza (3rd title) Atalanta Brescia Napoli |
| Relegated: | Cesena Alzano Virescit Savoia Fermana |
| League Topscorer: | Cosimo Francioso (24 goals) |
| Matches: | 380 |
| Total Goals: | 952 |
| Prevseason: | 1998–99 |
| Nextseason: | 2000–01 |
The Serie B 1999–2000 was the sixty-eighth tournament of this competition played in Italy since its creation.
Alzano, Fermana, Pistoiese and Savoia had been promoted from Serie C, while Salernitana, Sampdoria, Vicenza and Empoli had been relegated from Serie A.
| Team | Manager | Kit manufacturer | Shirt sponsor | |
|---|---|---|---|---|
| Alzano Virescit |  Claudio Foscarini | Virma | Valtellina SpA | |
| Atalanta | Giovanni Vavassori | Asics | Somet | |
| Brescia | Nedo Sonetti | Garman | Ristora | |
| Cesena | Paolo Ammoniaci | Adidas | CAMAC Industria Moda | |
| Chievo Verona | Lorenzo Balestro & Luciano Miani | Hummel | Paluani | |
| Cosenza | Bortolo Mutti | Kappa | Provincia di Cosenza | |
| Empoli | Silvio Baldini | Erreà | Sammontana | |
| Fermana | Ivo Iaconi | Fatto per fare | Teseo SpA | |
| Genoa | Bruno Bolchi | Kappa | Festival Crociere | |
| Monza | Roberto Antonelli | Legea | Vismara Salumi | |
| Napoli | Walter Novellino | Nike | Peroni | |
| Pescara | Giovanni Galeone | Puma | Gelati Gis | |
| Pistoiese | Andrea Agostinelli | Erreà | Vannucci Piante | |
| Ravenna | Attilio Perotti | Erreà | Valleverde Calzature | |
| Salernitana | Luigi Cagni | Asics | Exigo Jeans | |
| Sampdoria | Gian Piero Ventura | Asics | Dreamcast | |
| Savoia | Gaetano Manzi & Franco Mango | Hummel | Challoils | |
| Ternana | Tarcisio Burgnich | Ennedue | TAD Metals Ambiente | |
| Treviso | Gianfranco Bellotto | Lotto | Segafredo | |
| Vicenza | Edoardo Reja | Umbro | Caffè Vero |
A.C. Cesena relegated to Serie C1 2000-01.