This document specifies the method for the determination of the secant modulus of elasticity in compression of hardened concrete on test specimens which can be cast or taken from a structure. The test method allows the determination of two secant moduli of elasticity: the initial modulus, EC,0 measured at first loading and the stabilized modulus, EC,S measured after three loading cycles. Two different test methods are given. The first (Method A) is for determination of both initial and stabilized moduli, the second (Method B) is for determination of stabilized modulus only.