The 1951 Divizia B was the 12th season of the second tier of the Romanian football league system. The format with two series has been maintained, each of them having 12 teams. At the end of the season the winners of the series promoted to Divizia A and the last two places from each one of the series relegated to District Championship. Also this was the second season played in the spring-autumn system, a system imposed by the new leadership of the country which were in close ties with the Soviet Union.