Effects of cooling rate (at the time of solidification on the elastic constants of Cu₃Sn phase of Ag-Sn-Cu dental amalgam alloy were studied. In this study, three types of alloys were made, with the composition Cu-38-37 wt% Sn by means of casting, where each alloy was subjected to different cooling rate, such as cooling on the air (AC), air blown (AB), and quenched in the water (WQ). X-ray diffraction, metallography, and Scanning Electron Microscopy with Energy Dispersive Spectroscopy studies of three alloys indicated the existence of Cu₃Sn phase. Determination of the modulus of elasticity of Cu₃Sn (ε) phase was carried out by the measurement of longitudinal and transversal waves velocity using ultrasonic technique. The result shows that Cu₃Sn (ε) phase on AC gives higher modulus of elasticity values than those of Cu₃Sn (ε) on AB and WQ. The high modulus of elasticity value will produce a strong Ag-Sn-Cu dental amalagam alloy.