New halogen-substituted aromatic-aliphatic and wholly aromatic polyamides with high inherent viscosities were synthesized by the direct polycondensation of 5-halo-m-phenylenediamines, where the halogens were Cl, Br, and I, with both aliphatic and aromatic dicarboxylic acids in N-methyl-2-pyrrolidone with a mixture of triphenyl phosphite and pyridine as a condensing agent. The solubility of the halogen-substituted polyamides was much higher than that of the parent polyamides derived from m-phenylenediamine. The glass-transition temperatures of the substituted aromatic-aliphatic polyamides increased in the order Cl < Br < I, whereas the temperatures of 10% weight loss in air decreased in the reverse order. The limiting oxygen index values, as an indication of flammability, increased for the substituted aromatic-aliphatic polyamides in the order Cl < Br < I.