Alte Hauptpost Saarbrücken, Post office building in Saarbrücken, Germany.

Alte Hauptpost Saarbrücken is a wedge-shaped, U-plan former post office at the corner of Trierer Straße and St. Johanner Straße, built 1928/29 to designs by Ludwig Nobis on a plan by W. Hausmann. Its reinforced-concrete skeleton is infilled with brick, and the ground floor is framed by large round arches continued as blind arches holding round-arched windows. The southern corner projects like a tower; the brown-blue iron clinker ornament and the window bands below the flat roof are gone.

Built in 1928/29 as the Oberpostdirektion for the Saar Territory and Saarbrücken's main post office, the building was designed by Ludwig Nobis from a plan by W. Hausmann. After the 1935 Saar plebiscite it became the Reichspostdirektion Saarbrücken. Bombing in October 1944 destroyed the post office and halted postal services until April 1945. In 1947 the French military government renamed it Post-, Telegraphen- und Telephon-Verwaltung des Saarlandes.

The building's name changed with its rulers: from 1947 the French military government ran it as the Post-, Telegraphen- und Telephon-Verwaltung des Saarlandes, abbreviated POST SAAR on vehicles and SAAR POST on stamps. Two stamps of 1952–53, designed by Gabriel-Antoine Barlangue and Geiss, show the main post office; they were valid until 30 June 1957.

The building sits at the junction of Trierer Straße and St. Johanner Straße, its sharp-angled corner facing the crossing. The ground floor holds a L'Osteria restaurant with outdoor seating on the square in front, so the facade and arcade can be seen while stopping to eat. The state education ministry occupies the upper floors, which are not open to visitors.

The main post office appeared on two Saar-Post stamps issued in 1952 and 1953, worth 5 and 12 Saar-Franken, designed by Gabriel-Antoine Barlangue and Geiss; the print runs were 10,000,000 and 16,221,735 copies, valid until 30 June 1957.