The authors report the prepn. of soln.-derived metal oxide nanocomposite films by combining polyoxometalates (POMs) and colloidal oxide nanocrystals. Polyniobates and vanadates were combined with Sn-doped In2O3 (ITO) nanocrystals leading to Nb2O5-ITO, V2O5-ITO and VO2-ITO nanocomposite films. Compared to other soln.-phase methodologies, this approach offers excellent control of the nanoinclusion compn., size, morphol., and vol. fraction. Two different methodologies were used, which are based on the ex situ (in soln.) and in situ (within the film) ligand exchange of the pristine org. capping ligands of the nanocrystals by POMs. A thorough structural and compositional characterization of the films at different stages of the ligand exchange process is also presented.