| Administrator(s) | Test and County Cricket Board |
|---|---|
| Cricket format | Limited overs cricket(40 overs per innings) |
| Tournament format(s) | League |
| Champions | Derbyshire (1st title) |
| Participants | 17 |
| Matches | 136 |
| Most runs | 902 Jimmy Cook (Somerset) |
| Most wickets | 31 Waqar Younis (Surrey) |
The 1990 Refuge Assurance League was the twenty-second competing of what was generally known as the Sunday League. The competition was won for the first time by Derbyshire County Cricket Club.