The Tevatron collider at Fermilab provides a very rich
environment for the study of B_s mesons.  B_s Mixing is the most important
analysis within the B Physics program of both experiments.  In this paper we
summarize the most recent results on this topi+c from both D0 and CDF
experiments.  There were very important updates in both experiments after I
gave my talk, hence the organizers warmly recommended me to include the
latest available results on B_s mixing, instead of what I presented there.