A novel resinous composition used for coating comprising an amphoteric polyester resin whose acidic groups are capable of developing a resinous acid value are controlled in kind and are modified with saturated alicyclic acids and etherified amino-formaldehyde resins. This resinous composition is characterized by having all of the advantages possessed by oil-free polyester resin compositions in respect to weather resistance, the mechanical properties of the coating, interlaminar adhesion and the like, and furthermore, are excellent, inter alia, weather resistance because of be modified with saturated alicyclic acids. Also the curing properties are improved because of the control of the acidic groups and because the resins are amphoteric, they are compatible with melamine resins and have excellent pigment dispersibility. The invention also provides a coating composition containing as a vehicle, the abovementioned resinous composition.