Mechanical properties of nanocrystalline Ni made by Inert Gas Condensation and Electrodeposition are presented in relation to their microstructure. Significant plasticity is only observed at elevated temperatures for both types of nanocrystalline Ni. However, a higher temperature is needed in the Inert gas condensated material. Careful analysis of the microstructure by means of X-ray diffraction and conventional electron microscopy reveal initial differences in as-prepared samples. The change in microstructure during deformation at elevated temperatures and during heat treatment without external load is investigated and information about the deformation mechanisms is reported.