  We have conducted a photometric survey of the globular cluster NGC 6397 in a
search for variable stars. We obtained ~11h of time-resolved photometric images
with one ne European Southern Observatory-Very Large Telescope using the FOcal
Reducer and low dispersion Spectrograph imager distributed over two consecutive
nights. We analyzed 8391 light curves of stars brighter than magnitude 23 with
the 465 nm-filter, and we identified 412 variable stars, reaching ~ 4.8 +- 0.2
per cent of variability with timescales between 0.004 and 2d, with amplitudes
variation greater than +- 0.2 mag.
