Solution cast thin films of the Vectra(RM) HBA-HNA thermotropic liquid crystalline random copolymer, annealed for 1 h at 240 degrees C have been investigated by HREM. Non-periodic layer crystals were observed with the c* direction lying in, or close to the plane of the films, with crystalline core widths of about 10 nm. Lattice fringes were obtained from the 110 and 200 planes of the orthorhombic unit cell, and from the first of the non-periodic meridional maxima of the fibre diffraction pattern, these latter extending over the whole of the core widths.