The 1989–90 Segunda Divisão season was the 56th season of recognised second-tier football in Portugal. It was the last regionalized contest for the second tier championship, as a new Segunda Liga took shape as an unified second tier from the next season onwards.[1]
The last 4 classified in each series competed for against the teams classified in 6th place in each of the 6 series of the III Divisão and the 2 best 7th classified of the 6 series of the III Divisão (CD Fátima and Moura), in one hand. The 10 winners qualified for 1990–91 Segunda Divisão B, while the losers competed in 1990–91 Terceira Divisão.[2]