Minamiaso is a village in Aso District, Kumamoto Prefecture, Japan. It was formed on February 13, 2005 from the merger of the villages of Chōyō, Hakusui and Kugino. Neighbouring towns are Takamori, Ozu, and Nishihara. As of December 31, 2009, the village has an estimated population of 12,015 (5,776 male, 6,239 female) and a population density of 91.2 persons per km². The total area is 137.30 km².