The Bouleuterion/Odeion of Aizanoi is situated in the center of the ancient city. The rectangular structure has a semicircular cavea/koilon. Research conducted has shown that it remained in use from the first century AD into the Byzantine period, and that it served as a bouleuterion in the first phase and as an odeion in the second phase. Understood to have hosted important meetings and various events of the city the building was transformed for various functions in the later periods and the rows of seats in the cavea/koilon were dismantled for burning in kilns to make lime. This article deals with the layout, architecture, building phases and functions with preliminary assessments based on excavations.