Disclosed are a urethane having improved thermal insulation performance by lowering thermal conductivity of the urethane and a refrigerator comprising the same. The urethane may comprise: a plurality of closed cells containing inside gas; a plurality of open cells connected to outside air; and cell walls disposed between at least one of the plurality of closed cells and at least one of the plurality of open cells or between the plurality of closed cells to connect the at least one of the plurality of closed cells with the at least one of the plurality of open cells or to connect the plurality of closed cells. Diameters of a closed cell of the plurality of closed cells and an open cell of the plurality of open cells may be about 100 to 200 μm.