  The purpose of this paper is to show that RR Lyrae variables exist and can be
detected in M31 globular clusters. We report on the first tentative
identification of RR Lyrae candidates in four globular clusters of the
Andromeda galaxy, i.e. G11, G33, G64 and G322. Based on HST-WFPC2 archive
observations in the F555W and F814W filters spanning a total interval of about
5 consecutive hours we find evidence for 2, 4, 11 and 8 RR Lyrae variables of
both ab and c Bailey types in G11, G33, G64 and G322, respectively. Several
more candidates can be found by relaxing slightly the selection criteria. These
numbers are quite consistent with the horizontal branch morphology exhibited by
the four clusters, starting from the very blue HB in G11, and progressively
moving to redder HBs in G64, G33 and G322.
