The crystallization of isotactic poly(4-methylpentene-1) in its stable tetragonal crystal modification based on the 7(2) helix conformation was achieved on three different low molecular weight organic substrates and on polytetrafluoroethylene. The contact face was always the (100) face, although the details of the epitaxial relationships generated one, two, or even three chain axis orientations in the polymer epitaxial overgrowth.