1998 Italian motorcycle Grand Prix
The 1998 Italian motorcycle Grand Prix was the fourth race of the 1998 Grand Prix motorcycle racing season. It took place on 17 May 1998 at the Mugello Circuit.250 cc classification
The race was held in two parts as rain caused its interruption; aggregate times from the two heats determined the final result.125 cc classification
Championship standings after the race (500cc)
Below are the standings for the top five riders and constructors after round four has concluded.
;Riders' Championship standings
| Rider | Points |
| 1 |  Max Biaggi | 77 |
| 2 |  Mick Doohan | 70 |
| 3 |  Àlex Crivillé | 67 |
| 4 | Carlos Checa | 54 |
| 5 |  John Kocinski | 30 |
;Constructors' Championship standings
| Constructor | Points |
| 1 |  Honda | 100 |
| 2 | Yamaha | 45 |
| 3 | Suzuki | 36 |
| 4 |  Modenas KR3 | 24 |
| 5 |  MuZ | 4 |
- Note: Only the top five positions are included for both sets of standings.
