Blends of nylon 6 with the liquid crystal copolyester Vectra have been prepared from the melt with different compositions, and their thermal behaviour has been analysed by differential scanning calorimetry (d.s.c.) and Xray diffraction (WAXS) using syncrotron radiation, as a function of temperature and thermal treatment. The structural properties of these blends have been found to be very sensitive to the thermal history, and particular attention has been paid to the effect of the liquid crystal content in the polymorphic transformations of nylon 6.