Electrochemical insertion of ions in monoclinic tungsten(VI) oxide from aqueous solutions was investigated at room temperature. The solutions were nitric acid and solutions of Group I and II nitrates. In all the performed insertions, except with lithium nitrate, the obtained intercalates had the composition HxWO3 (0.07 < x < 0.84). Within this compositional range two types of hydrogen intercalated materials were obtained, both with tetragonal symmetry. For low degrees of insertion (0.07 < x < 0.17) the lattice constants were a = b = 5.225(2) and c = 3.884(4) A. For high degrees of insertion (0.50 < x < 0.84) the lattice constants were a = b = 5.358(2) and c = 3.749(5) A. With lithium nitrate as electrolyte solution intercalates with composition LixWO3 were obtained. After exposure to air the lithium intercalated compounds were tetragonal with lattice constants a = b = 5.1996(2) and c = 3.8402(1) A. The processes where barium nitrate was used as electrolyte were studied in detail, and the electrochemical processes were determined. The intercalates were characterized using X-ray powder diffraction, and Rietveld refinements of the structures of H0.12WO3 and LixWO3 were performed.