Thermal properties of the blends of polycarbonate (PC) and a thermotropic liquid crystalline polymer (LCP) prepared by screw extrusion have been investigated by differential scanning calorimeter (DSC). From the measured glass transition temperature (T-g) and specific heat increment (Delta C-p) at the T-g, the LCP appears to dissolve more in the PC-rich phase than does the PC in the LCP-rich phase. The polymer-polymer interaction parameter (chi(12)) and the degree of disorder (y/x(1)) of LCP in the PC-LCP blends were investigated using the lattice theory in which the anisotropy of LCP was taken into consideration. The chi(12) Of PC-LCP blend was calculated from the measured T-g and found to be 0.076 +/- 0.008 at 250 degrees C. The y/x(1) of LCP in amorphous phase was found to be increased with the increase of PC weight fraction in the PC-LCP blends.