Abstract Partially ordered polyarnide-hydrazides were produced by the poly condensation of diacid chlorides with aminobenz-hydrazides, the order that results being a consequence of the considerably more rapid reaction of a diacid chloride with the hydrazide group in competition with the aromatic amine group of the aminobenzhydrazide. Fibers were produced from a series of such polymers containing from 50 mole % meta-oriented phenylene rings to 100 mole % para-oriented ones. Fiber from the wholly para-oriented type of polymer exhibited very high strength and modulus: 12.5 and 468 g/den, respectively, at 4.3% elongation-to-break. Although the crystallinity and density observed for hot-drawn fibers of partially ordered completely para-oriented polyarnide-hydrazides were comparable to the crystallinity and density of fibers of the isomeric wholly ordered polymer, the partially ordered polymers were more readily spun to the ultra-high strength and high modulus type fibers, probably because their greater solubility made them easier to spin.