The Old Post Office building at No. 72 Knjaza Miloša Street in Aranđelovac is a structure that, in addition to its historical significance for the development of postal and telecommunication services, also holds value as an important example of urban architecture from the 19th century. It is a two-story building with a rectangular base, featuring a high ground floor and an attic space. The four-pitched roof is covered with beaver-tail tiles, and a prominent group of chimneys in the central part of the building adds to the visual completion of the structure's silhouette. It represents a classic type of bourgeois architecture, with decorative elements such as window and door frames, as well as noticeable rustic elements in the plinth. The openings are symmetrically arranged and modularly placed on the central façade, with five rectangular windows on the upper floor, corresponding to five attic entrance openings. The side façade features an original window with decorative plaster treatment. The upper floor is separated from the ground floor by a narrow cornice, while the roof cornice is more pronounced. The side façades, facing the cross street and the courtyard, have a uniform rhythm of windows. Based on preserved records that a post office existed in Aranđelovac in 1872, it is assumed that this building was already completed at that time.