Ab initio calculations of elastic moduli and theoretical uniaxial strength of composite lamina having continuous nano-fibre reinforcements are performed using pseudo-potential plane-wave code of Kresse
]. Obtained results are used to verify validity of macro-scale empirical relations for composites (rules of mixtures) [
] on the nano-scale. All quantities are computed from the dependence of crystal energy on a suitable deformation parameter. Results for tungsten nano-fibres in niobium matrix will be presented as a particular example of the ab-initio analysis.