Ba(Mg_1/3Ta_2/3)O₃ (BMT) compound is one of the most  studied complex perovskite oxide with adequate properties for microwave applications, such as filters or antennas. BMT thin films were obtained by a modified sol-gel method, using the spin coating technique. Pt-coated Si or α-Al₂O₃ plates were used as substrates. X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron microscopy and atomic force microscopy were employed for compositional, structural and morphological characterization of BMT samples. BMT thin films present single-phase compositions and cubic structure. The dielectric properties of BMT thin films were investigated at low frequency.