Systems based on the combination of ferromagnetic (FM) thin films and two-dimensional (2D) transition metal dichalcogenides are currently of high interest in the context of spintronic devices. Here, we report on the fabrication of MoS2/(Fe3O4, Fe) heterojunctions by using chemical-based methods. FM thin films have been initially synthesized on top of Si/SiO2 substrates by chemical vapour deposition. The 2D-MoS2 nanosheets have been grown on top of the FM layers by following the sulfurization of a solid film precursor of molybdenum oxide evaporated at the FMs surface. A comprehensive structural, chemical, morphological and magnetic characterization has been carried out at each step of the process. Several bottlenecks in the fabrication of MoS2/(Fe3O4, Fe) systems have been evidenced, the most critical being the sulfurization process, in which we detect a pronounced tendency of S to react with the …