A dynamic method of measuring the Young's modulus of elasticity of a solid has been developed. This uses the resonance in the flexural vibrations of loaded fixed-free bars at frequencies below 200 c/s. The frequency equation has been derived for a fixed-free prismatic bar, carrying a heavy mass of precise finite dimensions at the free end. The technique, which is workable at low temperatures, has been tested by measuring the Young's modulus for some specimens in the form of stiff rods at room temperature. The results are found to be reproducible to the order of 1%.