Synthesis of MoO2 nanoparticles with one-dimensional (1D) and spherical morphologies in aqueous solutions, through hydrothermal process was investigated. The materials were studied by x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Infrared spectroscopy (FTIR) and thermal analysis (TG). It was found that the quantity of organic compound influenced the size and shape of the final product. The possible formation mechanism of MoO2 microspheres and nanowires was also discussed. The conductivity of MoO2 nanowires was explained by the presence of two protons types in the material.