The CLASH-VLT VIMOS Large Programme builds on the CLASH Hubble Space Telescope multi-cycle treasury programme to carry out a comprehensive spectroscopic campaign on 13 massive galaxy clusters in the southern sky, at a median redshift of 0.4. Observations are 95% complete and provide spectroscopic identification for 500 to 1000 members per cluster, and over 200 background lensed galaxies at z 〈 7. When combined with a homogeneous set of multi-wavelength ancillary observations, this project will allow a determination of cluster mass density profiles with dynamical and lensing methods and a characterisation of the inner structure of cluster dark matter halos with unprecedented accuracy. The final spectroscopic CLASH-VLT dataset will contain ~ 30 000 spectra and redshifts, of which ~ 7000 are cluster members, providing a long-lasting legacy for studies of galaxy evolution in different environments.