Sequential copolymers of glycine and nylons 6,10 and 12,10 have been prepared by incorporating single glycine units at both ends of the diamine. These polymers have been obtained by interfacial polymerization and subsequently characterized by infrared and n.m.r. spectroscopies together with thermal analysis. The structure and morphology of lamellar crystals have also been investigated by X-ray diffraction and transmission electron microscopy, both imaging and diffraction. Additional data have been obtained from uniaxially oriented fibres. Results described in this paper complete previous studies on the incorporation of glycine units in nylons derived either from omega-amino acids or from diamines and diacids.