The reconstruction of the five Länder (federal states) on GDR territory was an important step towards German unity. In 1952 the old states had been replaced by a larger number of administrative districts. In July 1990 the GDR parliament passed the Establishment of Länder Act. 

Elections were held in the five new Länder on 14 October. The CDU emerged as the strongest party in four of the new states. The CDU also won the majority of votes in the first all-German parliamentary election on 2 December 1990. The civil rights organisations succeeded in winning seats in all the East German Länder assemblies and in the national parliament. The PDS (the successor to the old single state party, the SED) also won seats throughout the country.

The first all-German parliament met in the Reichstag in Berlin on 20 December. The elected members of the GDR parliament took their seats in the Federal Parliament in Bonn only a day after the celebrations for the Day of German Unity. The elections in December finally gave full legitimacy to them and their fellow parliamentarians from West Germany. At the same time as the general election, Berlin held its first citywide elections for its House of Representatives since 1946.in den Bundestag in Bonn eingezogen. Mit den Wahlen im Dezember erhalten sie und ihre westdeutschen Parlamentskollegen nun ihre volle Legitimität. Parallel zu den Bundestagswahlen findet in Berlin die erste Gesamtberliner Wahl zum Abgeordnetenhaus seit 1946 statt.