  We study the effect of squark generation mixing on squark production and
decays at the LHC in the Minimal Supersymmetric Standard Model (MSSM). We show
that the effect can be very large despite the very strong constraints on quark
flavour violation (QFV) from experimental data on B mesons. We find that the
two lightest up-type squarks ${\tilde u}_{1,2}$ can have large branching ratios
for the decays into $c {\tilde\chi_1^0}$ and $t {\tilde\chi_1^0}$ at the same
time, leading to QFV signals '$p p \to c \bar t\, (t \bar c)$ + missing-$E_T$ +
$X$' with a significant rate. The observation of this remarkable signature
would provide a powerful test of supersymmetric QFV at LHC. This could have a
significant impact on the search for squarks and the determination of the
underlying MSSM parameters.
