The name and the achievements of Aleksandar Deroko shine brightly in the constellation of Serbian architectural history. Deroko actively contributed to the Serbian twentieth-century architecture as a distinguished professor at the University of Belgrade, a prolific author, esteemed scholar, designer, and a highly driven heritage enthusiast. However, though recognised by his contemporaries and successors alike, Deroko's design activity has not yet been thoroughly examined. Exploring residential buildings designed for Deroko's Belgrade clientele, this paper widens the knowledge of his architectural production. Deroko's well-known passion for architectural history and extensive research of the Serbian vernacular buildings serve as a starting point for the study of his residential structures in Belgrade. Was Deroko's design process influenced by his deep appreciation for architectural past, and by the results of his findings? Or has he only adopted the formal characteristics of historic styles and vernacular architecture in his work? If so, to what extent? Discussing five structures built in the interwar period - house of Colonel Elezović, the Rakić villa, the Simić villa, the Marinković villa, the Stakić villa and the architect's personal villa - the paper traces transformation of Deroko's architectural inspiration, from typical academic historicist eclecticism to vernacular construction.