In 1958 Rau was elected a member of the "Landtag" (state parliament) of North Rhine-Westphalia. In 1967 he became chairman of the SPD group in the Landtag, and in 1970 Minister of Science and Education in the cabinet of Minister President Heinz Kühn. He founded five universities in North Rhine-Westphalia during the 1970s. He also started Germany's first distance learning university at Hagen (modelled on the "Open University" in Britain).