Heteroepitaxial growth of BaxSr1-xTiO3 thin films and their ferroelectric properties were reviewed. Lattice misfit strain could be introduced in the heteroepitaxial films, when they were grown with rf magnetron sputtering. It was confirmed from hysteresis measurements that the Curie temperature of the heteroepitaxial films could be artificially raised to higher than 200°C. A ferroelectric hysteresis loop could be observed even when the thickness of BaTiO3 was reduced to 12nm, which contained about 30 unit cells of the crystal in parallel to the polarization axis. Based on the results of a series of studies, it is expected that heteroepitaxial BaxSr1-xTiO3 films can be used in ferroelectric nonvolatile memories with a large-scale integration. The BaxSr1-xTiO3 films will provide chemically stable memory cells with good reproducibility and compatibility with the Si process, because they are free from volatile elements such as Pb or Bi. Further investigation and development will be required to improve the ferroelectric properties of the heteroepitaxial capacitors, especially on Si substrates.