| Dates | 26 April – 21 September 1990 |
|---|---|
| Administrator | England and Wales Cricket Board |
| Cricket format | First-class cricket |
| Tournament format | League system |
| Champions | Middlesex (9th title) |
| Participants | 17 |
| Matches | 187 |
| Most runs | Jimmy Cook, (Somerset) 2,432 |
| Most wickets | Neil Foster, (Essex) 94 |
The 1990 Britannic Assurance County Championship was the 91st officially organised running of the County Championship. Middlesex won the Championship title.
The Championship was sponsored by Britannic Assurance for the seventh time.
| Team | P | W | L | D | Bat | Bowl | Pts | |
|---|---|---|---|---|---|---|---|---|
| 1 | Middlesex | 22 | 10 | 1 | 11 | 73 | 55 | 288 |
| 2 | Essex | 22 | 8 | 2 | 12 | 73 | 56 | 257 |
| 3 | Hampshire | 22 | 8 | 4 | 10 | 67 | 48 | 243 |
| 4 | Worcestershire | 22 | 7 | 1 | 14 | 70 | 58 | 240 |
| 5 | Warwickshire | 22 | 7 | 7 | 8 | 55 | 64 | 231 |
| 6 | Lancashire | 22 | 6 | 3 | 13 | 65 | 56 | 217 |
| 7 | Leicestershire | 22 | 6 | 7 | 9 | 61 | 53 | 210 |
| 8 | Glamorgan | 22 | 5 | 6 | 11 | 64 | 48 | 192 |
| 9 | Surrey | 22 | 4 | 3 | 15 | 54 | 64 | 190 |
| 10 | Yorkshire | 22 | 5 | 9 | 8 | 52 | 55 | 187 |
| 11 | Northamptonshire | 22 | 4 | 9 | 9 | 61 | 60 | 185 |
| 12 | Derbyshire | 22 | 6 | 7 | 9 | 58 | 52 | 181 |
| 13 | Gloucestershire | 22 | 4 | 7 | 11 | 51 | 58 | 173 |
| 14 | Nottinghamshire | 22 | 4 | 8 | 10 | 51 | 58 | 173 |
| 15 | Somerset | 22 | 3 | 4 | 15 | 73 | 45 | 166 |
| 16 | Kent | 22 | 3 | 6 | 13 | 69 | 35 | 152 |
| 17 | Sussex | 22 | 3 | 9 | 10 | 51 | 44 | 143 |