The 1989–90 Divizia B was the 50th season of the second tier of the Romanian football league system.
The format has been maintained to three series, each of them having 18 teams.
At the end of the season the winners of the series promoted to Divizia A and the last three places from each series relegated to Divizia C. A relegation play-off was played between the 15th places from each series, team ranked last also relegated to Divizia C: the relegation play-off was necessary due to the fall of communism in December 1989, culminating with the exclusion from Divizia A of Flacăra Moreni and Olt Scornicești, and the dissolution of Victoria București.
The 15th-placed teams from each series of Divizia B played a relegation play-off.
The play-off was held in Bucharest and the team ranked last at the end of the tournament relegated to Divizia C.