Abstract. Asmara A, Dahlan Ma, Rani C. 2013. Ecological status on the density of coral predator Acanthaster planci related to the condition of coral reefs in Tomia waters, Wakatobi National Park, Southeast Sulawesi. Bonorowo Wetlands 3: 1-11. Acanthaster planci, otherwise known as the Crown of Thorns Starfish, is a giant starfish with many thorns and a coral-eating animal. This animal is scattered in various waters, overgrown by several coral types. This study aimed to determine: (i) the ecological status of A. planci in Tomia waters, Wakatobi National Park, (ii) the ecological condition of coral reef in Tomia waters, Wakatobi National Park, and (iii) the relation between the density of A. planci with the coral reef condition (live coral cover and dead corals). The research was conducted by survey and location determination in five stations from nine villages in the Tomia sub-district. Field data sampling was conducted by assessing coral reef conditions based on the line intercept transect (LIT) method, calculating the number of A. planci at a transect line, and measuring environmental parameters such as water flow, temperature, salinity, turbidity, and depth. The results showed that the density of A. planci in Tomia waters in a threatening status was found at Waha Station with a depth of 3-5 m and a density of 0.132 individual/m2. In contrast, the status was still normal in other stations, with a density of A. planci ranging from 0.000 up to 0.012 individuals/m2. The condition of live coral cover in Tomia waters, at 3-5 m in depth at Waitii Barat and Patua 1 Stations were still in good condition, while in Waha (II), Waha (III), and Onemay Stations in a medium category (critical). The depth of 10-13 m at Waitii Barat and Waha (II) Stations were still in a good category, and in Waha (III) Station, Onemay and Wali were in a medium category (critical). The density of A. planci in Tomia waters was negatively correlated with live coral cover and positively related to dead coral cover, but not significantly. However, in the high-density conditions of A. planci, such as at Waha Station with a depth of 3-5 m, the high density of A. planci caused a relatively high decrease in live coral cover and dead coral elevation.