The Mikołajowski House in Tarnów, also known as the Koruszowska Tenement, is a historic Gothic-Renaissance building erected in the 16th century, considered the oldest tenement house in the city. Located at Cathedral Square, the building features a two-story structure, mixed construction systems, and a fully developed basement. The architecture of the object exhibits many Gothic features, such as window and portal frames made of sandstone, as well as barrel vaults in the cellars. The interiors are adorned with Gothic-Renaissance portals, and one of the rooms preserves 16th-century polychromes. The building's functional use has been diverse; over the centuries, it served as housing for the clergy, schools, and was the seat of the Museum of Hygiene and the District Health Center. In the 19th century, it was a place of education, and in the 20th century, it underwent numerous revitalizations aimed at adapting it for museum functions. In 1991, it was entered into the register of monuments. Its facade is modest, three-axis, and devoid of decorations, but the entrance portal is richly decorated, including the image of the Kościesza coat of arms. The building houses collections of folk and religious art, including church paraments from various eras. Interestingly, the house was the subject of numerous transactions and changes of ownership over the years, which testifies to its importance in local history.