Electron beam induced deposition (EBID) is a process used for the fabrication of three-dimensional nanostructures of a variety of materials, but direct deposition of pure metallic structures has rarely been achieved. Typically, MeCpPtMe3 as a precursor for Pt leads to a carbon rich deposit with ~15 at.% Pt, which negatively affects its application as an electrical contact. We report a new process for Pt purification: in situ annealing with electron beam post-irradiation under oxygen flux, which can completely purify a thin (<100 nm) Pt EBID structure at substrate temperatures as low as 120 °C. We have developed a sequential method in which a thin Pt EBID structure is deposited on a previously purified structure and subsequently purified. The resistivity of the contact grown by this sequential procedure is observed to be ~70 ± 8 μΩ cm-only six times higher than that of pure bulk Pt. Thus, sequential deposition and purification proves to be an effective method for fabricating pure Pt structures of desired dimensions.