  The LHCb collaboration has measured central exclusive production of $J/\psi$,
$\psi(2S)$, and $\Upsilon$ mesons as well as $J/\psi J/\psi$, $J/\psi\psi(2S)$,
$\psi(2S)\psi(2S)$, and $\chi_c\chi_c$ meson pairs in proton-proton collisions.
The analyses of $\Upsilon$ and charmonium pairs are performed at the
centre-of-mass energies of 7 TeV and 8 TeV, and those of $J/\psi$ and
$\psi(2S)$ are done at 7 TeV and 13 TeV. The analysis at 13 TeV involves the
use of new shower counters. These allow a reduction in the background by
vetoing events with activity in an extended region in rapidity. The
measurements of central exclusive production at LHCb are sensitive to gluon
distributions for Bjorken-$x$ values down to $2\times10^{-6}$ (at 13 TeV). An
overview of the LHCb results is presented and compared to existing measurements
of other experiments and theoretical calculations.
