The effect of iodine treatment on the uniaxial tensile drawing of an ethylene/vinyl-alcohol copolymer containing 44 mol% of ethylene units is studied as a function of draw temperature and iodine concentration. Drawing, between 60 and 100 degrees C, of films soaked in a 0.125 M iodine solution involves complexation of the amorphous phase as judged from X-fay diffraction. The monoclinic crystalline phase turns into the mesomorphic form. Drawing films soaked in a 0.5 M solution brings about complexation of the crystalline phase in addition to the amorphous phase. Miyasaka＇s model of substitution solid solution is assumed for the crystalline complex. It is suggested in addition that the mesomorphic form is a host structure for the complex. Drawing above 100 degrees C involves segregation of molecular iodine accompanied by disruption of both the crystalline complex and the pure copolymer crystal. It is suggested that the polyiodides dissociate into molecular iodine which partly separates and crystallizes into purr domains and partly dissolves into the polymer crystals and breaks them down. Biaxial drawing of films soaked in 0.5 M solution has been carried out successfully at 90 degrees C. Soaking into sodium thiosulfate solution removes iodine and regenerates a purr copolymer film in a biaxially oriented state.