For a long time the B0(s)-B-bar0_s system has eluded a
complete investigation of its observables.  Only recently the Tevatron
experiments have accumulated sizable B0(s) samples, which allow a direct
and precise study of the system properties.  This contribution reviews
the most up-to-date measurements by the CDF and D0 Collaborations of the
B0(s)-B-bar0_s system parameters: the mass and decay width differences,
Delta m_s and Delta Gamma_s, between the heavy and light B0(s) mass
eigenstates, the average decay width Gamma_s, and the CP-violating phase
in the mixing phi_s.