  Exclusive J/psi production, gamma* p -> J/psi p, offers a unique opportunity
to determine the gluon density of the proton in the small x domain. We use the
available HERA data to determine the gluon distribution in the region 10^{-4}
<~ x <~ 10^{-2} and 2 <~ Q^2 <~ 10 GeV^2, where the uncertainty on the gluon
extracted from the global parton analyses is large. The gluon density is found
to be approximately flat at the lower scale; it is compared with those of
recent global analyses.
