A film iodinated at solution state before casting (BIBC film) and a film iodinated after casting (BIAC film) were prepared by casting an aqueous solution of poly(vinyl alcohol) (PVA) including I-2/KI and boric acid, and by successively soaking the PVA film in aqueous solutions of boric acid and I-2/KI, respectively. The boric acid-induced and I-2/KI-induced weight gains relative to the PVA were 3, 5, 7, and 10%, and 3, 5, 10, and 20%, respectively. The effects of boric acid and iodine on the crystallinity and drawability of the films were investigated. Although the crystalline structure of the BIAC films was not affected by boric acid, the boric acids in the PVA solution containing I-2/KI may have formed intra-molecular cross-links on the PVA chain to accelerate the formation of the PVA-iodine complex evenly, and subsequently interrupt the PVA crystallization through the BIBC film formation to render the resultant film slightly crystalline or practically amorphous. This occurred even at a much lower I-2/KI-induced weight gain (20%) than the minimum weight gain (125%) at which the iodinated at solution state before casting film without boric acid indicated a practically amorphous state. The maximum draw ratio of the films generally decreased with increasing boric acid content, which was mainly attributed to the increase of the extended segments of the PVA chains in the amorphous region due to the cross-links formed with the boric acids. The maximum draw ratios of the BIBC films tended to decrease more severely than those of the BIAC films.