| Competition: | Serie A |
| Season: | –90 |
| Dates: | 27 August 1989 – 29 April 1990 |
| Winners: | Napoli 2nd title |
| Continentalcup1: | European Cup |
| Continentalcup1 Qualifiers: | Napoli Milan |
| Continentalcup3: | UEFA Cup |
| Continentalcup3 Qualifiers: | Internazionale Roma Atalanta Bologna |
| Continentalcup2: | Cup Winners' Cup |
| Continentalcup2 Qualifiers: | Juventus Sampdoria |
| Relegated: | Udinese Hellas Verona Cremonese Ascoli |
| League Topscorer: | Marco van Basten (19 goals) |
| Longest Wins: | 22 matches Milan |
| Longest Unbeaten: | 17 matches Milan |
| Longest Losses: | 17 matches Ascoli |
| Longest Winless: | 4 matches Ascoli |
| Matches: | 306 |
| Total Goals: | 684 |
| Prevseason: | 1988–89 |
| Nextseason: | 1990–91 |
The 1989–90 Serie A season was another successful year for Napoli, with Diego Maradona being among the leading goalscorers in Serie A (16 goals), behind Marco van Basten of Milan (19 goals) and Roberto Baggio of Fiorentina (17 goals). But while Baggio's Fiorentina narrowly avoided relegation, Maradona's Napoli won their second Serie A title in four seasons, while Van Basten helped Milan retain the European Cup as compensation for their failure to win the Serie A title, having finished two points behind Napoli. Demoted to Serie B for 1990–91 were Udinese, Hellas Verona, Cremonese and Ascoli. In Europe, Sampdoria won the Cup Winners Cup and Juventus the UEFA Cup, making this year the most successful in Italian football history.
Genoa, Bari, Udinese and Cremonese had been promoted from Serie B.
| Team | Head coach | Kit manufacturer | Shirt sponsor | |
|---|---|---|---|---|
| Ascoli |  Aldo Agroppi | Adidas | Cocif | |
| Atalanta | Emiliano Mondonico | Ennerre | Tamoil | |
| Bari | Gaetano Salvemini | Adidas | Sud Leasing | |
| Bologna | Luigi Maifredi | Uhlsport | Mercatone Uno | |
| Cesena | Marcello Lippi | Adidas | Orogel | |
| Cremonese | Tarcisio Burgnich | Patrick | Majestic SpA | |
| Fiorentina | Francesco Graziani | ABM | La Nazione | |
| Genoa | Franco Scoglio | Erreà | Mita | |
| Hellas Verona | Osvaldo Bagnoli | Hummel | Tortellini Rana | |
| Internazionale | Giovanni Trapattoni | Uhlsport | Misura | |
| Juventus | Dino Zoff | Kappa | UPIM | |
| Lazio | Giuseppe Materazzi | Umbro | Cassa di Risparmio di Roma | |
| Lecce | Carlo Mazzone | Adidas | Ponti Aceto | |
| Milan | Arrigo Sacchi | Kappa | Mediolanum | |
| Napoli | Alberto Bigon | Ennerre | Mars | |
| Roma | Luigi Radice | Ennerre | Barilla | |
| Sampdoria | Vujadin Boškov | Kappa | Erg | |
| Udinese | Rino Marchesi | ABM | Rex Elettrodomestici |
| Rank | Player | Club | Goals |
|---|---|---|---|
| 1 | Milan | 19 | |
| 2 | Roberto Baggio | Fiorentina | 17 |
| 3 | Napoli | 16 | |
| 4 | Juventus | 15 | |
| 5 | Roma | 14 | |
| 6 | Cesena | 13 | |
| Cremonese | |||
| Internazionale | |||
| 9 | Udinese | 11 | |
| Sampdoria | |||
| Internazionale |