  $\chi^2$ vetoes are commonly used in searching for gravitational waves, in
particular for broad-band signals, but they can also be applied to narrow-band
continuous wave signals, such as those expected from rapidly rotating neutron
stars. In this paper we present a $\chi^2$ veto adapted to the Hough transform
searches for continuous gravitational wave signals; we characterize the
$\chi^2$-significance plane for different frequency bands; and discuss the
expected performance of this veto in LIGO analysis.
