A process for manufacturing a metallized polymeric film to provide a structure possessing high metal-to-film adhesion and little, if any, tendency toward metal fracture is disclosed. In one embodiment of the process, at least one polyolefin layer is provided to a film which includes a substantially isotactic polymer having a degree of atacticity of no more than about 6%. The isotactic component is preferably polypropylene homopolymer. Other components include up to about 34% of an adhesive-promoting component which can be a C.sub.2 -C.sub.4 polymer, including homo-, co-, and terpolymers having C.sub.2 -C.sub.4 carbon chains, and a second isotactic polymer having a degree of atacticity of from about 6% to about 15%. The surface of the polyolefin layer is subjected to flame treatment followed by vacuum metallization of this surface (preferably with aluminum).