The LaCoO3 belongs to the class of compounds called Mott insulators. These oxide perovskite-type cobaltites with p-type are considered alternative materials to improve the efficiency of the process of conversion of energy in thermoelectric devices. The interest in LaCoO3 is mostly related to its non-magnetic ground at low temperature. We have fabricated LaCoO3 thin films via an RF magnetron sputtering technique using high-oxygen pressure at 600°C on (100)-Si substrates. The target for the growth of the films was prepared by a solid state reaction method. The crystalline structure of the films was determined by X-ray diffractometry showing that the LaCoO3 main peaks correspond to the (001) preferential orientation. X-ray measurements also indicated that the formation of LaCoO3 was complete, and it was verified that a pure phase with rhombohedral crystalline structure was obtained. The film surfaces were characterized by atomic force microscopy (AFM) in the non-contact mode. AFM micrographs showed homogeneous surfaces in the films with average roughness values of 1.06 nm, and 3.49 nm for samples with 40 nm and 120 nm of thickness respectively. The magnetic properties of the samples were characterized via isothermal hysteresis curves, between 100 and 300K, using a vibrating sample magnetometry (VSM) technique. The curves showed a hysteretic behavior with a saturation field that decreases with the increasing of temperature.