Polycarbonate blends containing a thermotropic liquid crystalline polymer were prepared in a laboratory-scale internal mixer at various blend compositions, rotor speeds and mixing temperatures. The effect of deformation history on morphology and rheological properties of blends was studied by means of scanning electron microscopy and capillary rheometer. Characteristic torque values of blends were observed to be minimum at 100 rpm, and LCP particles were no fibril formation because of low shear rate of internal mixer. It was found the viscosity of blends was much lower than that of the neat polymer alone, and the addition of as little as 5 weight percent LCP resulted in 5 times drop in viscosity. The total mixing energy and the viscosity of blends were observed to be minimum at LCP composition of about 30 weight percent. Furthermore, in capillary experiments the dispersed phase occured the formation of fibrils under the shear field which the viscosity ratio of the dispersed to matrix phase is around unity or less. Based on the DSC results, it is concluded that the reduction of T_g of PC resulted from the partial increase of miscibility due to transesterification reaction supported by infrared spectroscopy.