Blends of diglycidyl ether of bisphenol-A epoxy resin and adipic acid, ethylene glycol, diethylene glycol polyester copolymer have been studied regarding viscosity behavior. Both the rheological measurements carried out on the molten mixtures over a large interval of shear rates and the intrinsic viscosity of the blend solutions pointed to an immiscibility at temperatures ranging from 30° to 90°C. The rheological parameters evaluated on the flow of the mixtures against temperature and the shear rate led to the conclusion that the tested blends have a non-Newtonian rheological behavior of the pseudoplastic type.