Saiki (佐伯市, Saiki-shi) is a city located in Ōita Prefecture, Japan. The city was founded on April 29, 1941. On March 3, 2005, Saiki merged with the towns of Kamae, Kamiura, Tsurumi, Ume and Yayoi, and the villages Honjō, Naokawa and Yonōzu (all from Minamiamabe District) to create the new and expanded Saiki City. Minamiamabe District was dissolved as a result of this merger. As of March 2017, the new city has an estimated population of 73,546 (former city, 2003: 49,183) and a population density of 81 persons per km2. The total area is 903.44 km2, making it the largest city by area in Kyushu.