  We present the ETMC results for the bag parameters describing the neutral
kaon mixing in the Standard Model and beyond and preliminary results for the
bag parameters controlling the short distance contributions in the
D^0-\bar{D}^0 oscillations. We also present preliminary results for the B_{Bd},
B_{Bs}, B_{Bs}/B_{Bd} and \xi -parameter controlling B^0_-\bar{B}^0
oscillations in the Standard Model employing the so-called ratio method. Using
Nf=2 maximally twisted sea quarks and Osterwalder-Seiler valence quarks we
achieve both O(a)-improvement and continuum like renormalization pattern.
Simulations are performed at three-values of the lattice spacing and several
values of quark masses in the light, strange, charm region and above charm up
to ~2.5m_c. Our results are extrapolated to the continuum limit and
extrapolated/interpolated to the physical quark masses.
