The aim of this paper was to examine the effect of titanium substrate structure refinement (to the nanometric scale) on the chemical and phase composition of Ti‐Al intermetallic layers. The material examined in the study was commercially available pure titanium with average grain size of 65 μm and 60 nm. The aluminium layer with thickness of 5 μm were obtained on both substrates using magnetron sputtering technique. After annealing more phase from Ti – Al system on nano‐crystalline titanium were observed compared to micro‐crystalline one. The obtained intermetallic layer was thicker and more homogeneous on nano‐crystalline substrate. The grain size of the substrate was effected on the topography, thickness and microstructure of the diffusive Ti‐Al layers. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)