  The microlensing of background stars by compact objects in globular clusters
is analyzed. The main strength of the proposed search is the direct
relationship between the lens mass and the time scale of the microlensing
event. The main problem is the low overall rate of expected events which
implies that a ground based search should last for about a decade to generate a
non trivial number of events, like a few dozen. A space borne experiment could
increase the rate by a large factor by increasing the number of stars which
could be monitored thanks to the much better seeing. The clusters M22 with the
galactic bulge background, and 47 Tuc with the SMC background, are the two
examples of possible targets.
