To obtain a foamable polyurethane elastomer composition using inexpensive MDI and giving an elastomer scarcely generating permanent compression set and having sufficient load resistance, sufficient flexibility and excellent moldability, and a vibration-proof material.

This foamable polyurethane elastomer composition comprises (A) an isocyanate-terminated prepolymer comprising (A-1) an isocyanate compound and (A-2) a polyol component and (B) a foaming component comprising water, a foam stabilizer and a catalyst. Therein, the component A-1 in the component A is 4, 4'-diphenylmethanediisocyanate, and the component A-2 is a polyol containing a polyetheresterpolyol having an average functional group number of 2.1-2.5 and produced from (A-2-1) a triol compound, (A-2-2) a polyoxyalkylene glycol and (A-2-3) an aliphatic dibasic acid.