This paper investigates the roof design in the projects by Vann Molyvann, a representative Cambodian modern architect in the Sangkum Reastr Niyum era of 1950s and 1960s. The research consists in following 4 parts: Chapter 2 explicates his thought on Tradition and Modern and Chapter 3 describes his educational background behind the thought. From chapter 4 to 6, the roof designs in his works are analyzed chronologically. Its transition are explained as the result of the conflict and integration of three archetypes; 'steeple', 'gable', and 'flat roof', which originate from Angkor temples, Stupas, Khmer timber houses, and Modern Movement.
