The crystallisation behaviour and morphology of polyethylene-based single polymer composites has been investigated by light microscopy and low voltage scanning electron microscopy techniques. The surface crystals on ultra high molecular weight polyethylene fibres act as nucleation centres for the high density polyethylene matrix, which may result from epitaxial crystallisation. After crystallisation from the melt and independent of air-cooled or isothermal crystallisation conditions, a transcrystalline layer was found having lamellar crystals grown perpendicular to the fibre axis.