Discussed here are high damping structural materials in which damping materials are interlaminated with carbon fiber reinforced plastics (CFRP). Damping properties under longitudinal vibration were evaluated using [+θ/-θ] s angle-ply based laminates. Loss factor values for these laminates are 0.015-0.1, which are 2 to 20 times as large as that for conventional CFRP. Theoretical and FEM analysis were used to predict the damping properties. Good agreement was obtained between these predictions and the experimental results at low temperature range.