We report the latest results on the measurement of
the Bs-Bsbar oscillation frequency using 1 fb-1 of
data from ppbar collisions with the CDF II detector
at the Fermilab Tevatron. We measure the probability
as a function of proper decay time that the Bs
decays with the same, or opposite, flavour as its
flavour at production, which is determined using
opposite-side and same-side flavour identification
methods. We find a signal consistent with Bs-Bsbar
oscillations.