Polyamides are one of the most widely used engineering plastics. Aliphatic polyamide represented by nylon has been previously synthesized by an interfacial polymerization reaction between an organic layer of diacyl chloride and a water layer of diamine. However, for more than 75 years, there has been no reported polymerization method that can enable the synthesis of both helical aliphatic polyamide (nylon) and aromatic polyamide (polyphthalamide) and can control their spiral morphologies. In this study, we developed a novel polymerization method based on chiral interfacial polycondensation using a chiral nematic liquid crystal (N*-LC) layer and a water layer and, for the first time, succeeded in synthesizing helical nylons and polyphthalamides with one-handed spiral morphologies. The swirling directions in the spiral morphology of the helical polyamides were controlled by selecting the chirality of the chiral dopant used for preparing the N*-LC. The present synthesis method should extend the applicability of asymmetric interfacial polymerizations using N*-LC to various types of polyamides.