PURPOSE: To provide a thixotropic unsaturated polyester coating composition which can give a good finishing appearance irrespective of the humidity during coating.

CONSTITUTION: A thixotropic unsaturated polyester coating composition comprising an unsaturated polyester coating composition mainly consisting of an unsaturated polyester resin obtained by condensing an acid component comprising an unsaturated dibasic acid and optionally other saturated dibasic acids with a glycol and an ethylenically unsaturated monomer, 1-15PHR of a hydrophobic silica and 1-20PHR of an organic thixotropant.