BaTiO3 thin films have been prepared on Ti-substrates using Ba-acetate solutions by the hydrothermal-electrochemical method in newly constructed flow-system equipment. The synthesis parameters (temperature of 120-200 degrees C, flow rate of 1-50 cm(3) min(-1)) allow fabrication of single-phase films with grain size in the range of 50-340 nm by controlling nucleation and/or growth rates. The flow can be closed, enabling easy recycling of the solutions used. This processing route may serve as an inexpensive and environmentally friendly way of fabrication of single-phase BaTiO3 thin films as well as functionally graded ferroelectric materials.