The present invention relates to an ink-jet ink composition, which comprises (A) a polybutadiene; (B) a radical polymerizable compound having a (meth)acryloyl group; (C) a radical polymerization initiator; and (D) a colorant. The ink composition is highly sensitive to activated radiant rays and can accordingly be cured in a high sensitivity when irradiated with the same, can maintain its flexibility even after the cure thereof and can accordingly be used suitably in the ink-jet recording method and a method for the preparation of a lithographic printing plate, to thus form printed matters and a lithographic printing plate having high printing durability.