Egg waste is a huge hazardous waste in the world, which requires a high cost to treat. The major compound in eggshells is calcium carbonate that can be converted into calcium oxide by the calcination method. This study was conducted to examine what are the ideal conditions that may affect perfect calcium oxide production in terms of temperature, contact time, and weight. The eggshells were pre-treated to eliminate dirt and unnecessary biological substance, ground into powder form, and sieved with 500 µm size. In this study,  the decomposition of eggshells to produce calcium oxide (CaO) were conducted at various conditions; (i) constant weight and contact time with different temperatures, (ii) constant temperature and weight with different contact times; and (iii) constant temperature and contact time with different weights. Primary characteristics of eggshell powder such as color changes, mass loss, bulk density, and moisture content, and identification of chemical bonds in a molecule were studied. The result showed significant differences in the color transition of the eggshell powder at parameter temperature and contact time. FTIR result reported that the grey color of calcined samples consists of calcium carbonate while solid white powder consists of metal oxide content. Calcined eggshell powder at a temperature of 900^oC can be considered as a broken organic compound due to its high temperature whereas the eggshell powder at a contact time of 6 hours showed that there is calcium oxide corresponded to the wavelength. Thus, it can be concluded that the optimum calcination condition is at a temperature of 900^oC with less than 3 hours contact time.