Electrorheological properties of binary mixtures of liquid-crystalline polymer and low molecular weight liquid crystal were investigated. The viscosity of the liquid-crystalline mixture increased by application of DC electric field and recovered its original viscosity after the electric field was turned off. The effect appears above a field strength of 1.0 kV/mm, and the viscosity increases with the electric field strength. For shear rate 2 s(-1) the viscosity was increased by approximately 5 times when 5.0 kV/mm was applied. Above nematic - isotropic transition temperature, electrorheological effect disappeared.