Annealing of crystal damage from ion implantation may result in dislocation formation. Here we study the nucleation, growth, and annihilation of such dislocations during rapid thermal anneals of Si, Ge, As, and In implanted Si. The dislocation formation process is observed for single or multiple damage profiles, as well as in amorphous-crystal transition regions. Dislocations initially nucleate in all these cases, even if they eventually annihilate during further annealing. It is also shown that for C implants in Si not only do dislocations not remain after annealing, but they do not even nucleate.