  Mass loss and axial rotation are playing key roles in shaping the evolution
of massive stars. They affect the tracks in the HR diagram, the lifetimes, the
surface abundances, the hardness of the radiation field, the chemical yields,
the presupernova status, the nature of the remnant, the mechanical energy
released in the interstellar medium, etc... In this paper, after recalling a
few characteristics of mass loss and rotation, we review the effects of these
two processes at different metallicities. Rotation probably has its most
important effects at low metallicities, while mass loss and rotation deeply
affect the evolution of massive stars at solar and higher than solar
metallicities.
