  We searched for a sidereal modulation in the MINOS far detector neutrino
rate. Such a signal would be a consequence of Lorentz and CPT violation as
described by the Standard-Model Extension framework. It also would be the first
detection of a perturbative effect to conventional neutrino mass oscillations.
We found no evidence for this sidereal signature and the upper limits placed on
the magnitudes of the Lorentz and CPT violating coefficients describing the
theory are an improvement by factors of $20-510$ over the current best limits
found using the MINOS near detector.
