Poly(amide-hydrazide)s were originally developed to give fibers of high modulus and high strength [1]. They were generally prepared 1) from dicarboxylic acid chlorides and aminohydrazides by low-temperature polycondensation [2,3]; 2) by the phosphorylation method [4, 5]; and 3) from dihydrazides with preformed amide linkages by low-temperature polycondensation [6]. These polymers were found to be thermally stable, but they showed poor solubility in polar aprotic solvents. In this paper we report the synthesis and characterization of some new poly(amide-hydrazide)s with azo groups in the backbone, which were introduced to improve solubility.