In recent years, there is a high demand for the development of light-weight metals foams. In this paper, the factors which affect the foaming in a foamed aluminum casting process were investigated. The powdered titanium hydride as a foaming agent was added to the molten aluminum alloy in the amount of 0.5 to 2.5% to adjust a proper amount of the foaming agent, and foaming condition was controlled in the temperature range, from 893 to 933 K, to determine the optimum foaming process to obtain a homogeneous aluminum foam. It was found that a properly controlled holding temperature and titanium hydride content of the melt were good for the acquirement of foamed aluminum which contains uniform cell structure of high porosity. The optimum foamed aluminum with air bubbles of 2 to 6 mm diameter and the uniform distribution with 86% porosity was obtained by the addition of 1.0% titanium hydride at 913 K.