Synopsis A study is reported of the energy dissipated in damage and in damping when cement paste prisms are loaded in uniaxial compression. Damage, characterized both by change in initial elastic modulus during sequential loading-unloading cycles and by the energy dissipated in damage, is detected at axial strains as low as 500 to 600 × 10−6 As the axial strain increases, the initial elastic modulus falls and the energy dissipated in damage gradually increases. Volumetric strain measurements indicate that the mechanism of fracture in cement paste in uniaxial compression is basically the same as in concrete: the formation of cracks introduces a dilating effect in opposition to the normal reduction in volume of the specimen under load. Whereas energy is only dissipated in damage during the first loading over a given strain range, it can be repeatedly dissipated by the damping process. The experimental data on cement pastes indicate that the energy dissipated in damping depends uniquely upon the strain range undergone by the specimen but that it is independent of the degree of damage in the specimen.