PURPOSE: A cold-setting alkyd resin coating composition having improved flexibility, drying characteristics, gloss, water resistance, etc., obtained by blending an alkyd resin with a specific cylcopentadiene oil.

CONSTITUTION: The desired composition comprising a mixture or a heated reaction product of (A) not less than 50wt% alkyd resin and (B) not more than 50wt% cyclopentadiene oil having a viscosity at 25°C 100W50,000 centipoise as vehicle ingredient. 95W50wt% ingredient A is preferably used with 5W50wt% ingredient B. A long-oil type alkyd resin modified by soybean oil is cited as the ingredient A, and a polymer obtained by polymerizing a mixture of monomers of dicyclopentadiene, 1,3-pentadiene, and vinyl acetate in the presence of xylene solvent under heating, etc. is cited as the ingredient B.