Post office in the colonial period was intended to provide more secure mail for residents, especially for those who traded from offices outside Java and for those who came from and went to the Netherlands. Since then the postal service has been born carrying out the role and function of service to the public. At that time, the Dutch East Indies government needed many new buildings in Medan including this post office since Medan city was growing rapidly as a result of plantations that could provide profitable results.

The building functioned as a post office from its inception until 2022, then it was turned into a commercial area under the name Pos Bloc. Construction began in 1909 and was completed in 1911. The building was the first major project for J. Snuyf, a Dutch architect who in 1909 became head of the public works department (BOW/Burgerlijke Openbare Werken) in colonial Batavia. Although the gevel (wall layer) and tower with dormer (skylight) are still visible, reminiscent of traditional Dutch architecture adapted to the tropical climate, the building was said by Dutch architect Cor Passchier to show an innovation at the time that illustrated a search for a new style (Transitional Architecture),

There used to be a fountain in front of the Post Office Building dedicated to one of the pioneers of the plantation city in Deli land, Jacobus Nienhuys, and this fountain point was the Zero Kilometer Point of Medan city, but now this fountain design has been demolished.
This building is one of the best and most attractive corner buildings in Medan city. There is a dome on the corner side, with an octagonal main hall (dome) that uses many openings for ornamentation and ventilation. The roof is a two-storey octagon with dormer windows (lucarn), and Dutch gables on other parts of the building. The openings are in the form of longitudinal rectangles and arches. Each opening is fitted with a lattice to filter light. At each corner of the arch-shaped wall there is an iron outboard lamp. The main door is arch-shaped and two-leafed. There is stained glass at the top of the west and east arch walls. In the central room, called the vestibule, an antique decorative lamp typical of the old days hangs at the top. The lamp, which is approximately ten meters high and about six meters above the floor, is original from the Dutch era. On the lower edge of the ceiling, several carrier pigeons are carved with old Dutch designs, different from the carrier pigeon carvings typical of Pos Indonesia.

In another room, to the left of the vestibule, there are three steel doors that are also part of the original post office building. One of them still functions as a door today. The way to open it is by being pulled up and down with a chain, which is characteristic of the old pulley system.
Currently, the Post Office building has been converted into a commercial area where the people of Medan gather. Basically, this building has not undergone significant changes, there is only additional space for retail locations and cafes without reducing the historical value and identity of the original building.