The 1990 Offaly Senior Hurling Championship was the 93rd staging of the Offaly Senior Hurling Championship since its establishment by the Offaly County Board in 1896.
Lusmagh entered the championship as the defending champions.
The final was played on 14 October 1990 at St Brendan's Park in Birr, between St Rynagh's and Birr, in what was their fourth meeting in the final overall. St Rynagh's won the match by 2âÂÂ06 to 1âÂÂ07 to claim their 14th championship title overall and a first championship title in three years.