The article is devoted to the interior design, furnishings, and functions of socialist realism-style buildings of the Administrative Centre of the Lenin Metallurgical Plant in Nowa Huta. It is a complex consisting of two buildings, of which the Z Building – the northern one – was intended for the factory’s management, and the S Building – the southern one – was intended for “social” amenities. Each of the two buildings, despite their external appearance of nearly identical twins, received a different interior design, consistent with its intended use. Deciphering the original arrangement of individual rooms was possible thanks to the survival of some of the interiors in a relatively good condition, as well as the analysis of the meticulous executive documentation of the entire complex preserved to this day, and the so-called perspektywki [“perspectivettes”] – published drawings by the head of the interior design team, professor Marian Sigmund, depicting the appearance of selected spaces. The Z Building served official functions, therefore the most important representative rooms were placed in its first floor: conference rooms, official halls, offices for the Metallurgical Combine’s managerial staff, as well as a number of office facilities. The whole was designed as a Gesamtkunstwerk. The interior design refers to the tradition initiated by Adolf Szyszko-Bohusz at the Wawel Royal Castle, continued in pre-war representative and office interiors, and even in those designed for the chancellery of the governor general in the 1940s. Building S was meant to serve another purpose, as it was conceived as a “social house”, and therefore its interiors were designed accordingly. The central room within the walls of the S Building is the theatre hall with a common room above it. In addition, the building contained: a dining room, a hotel, reading rooms, and a health centre. The interiors were arranged in a way that was devoid of pathos; they were given some features of modernist solutions, albeit dressed in a historical costume. The furniture was also created to match the interior design of individual spaces.