  We construct a CFT dual to string theory on AdS$_3$ with pure NS-NS flux. It
is given by a symmetric orbifold of a linear dilaton theory deformed by a
marginal operator from the twist-2 sector. We compute two- and three-point
functions on the CFT side to 4th order in conformal perturbation theory at
large $N$. They agree with the string computation at genus 0, thus providing
ample evidence for a duality. We also show that the full spectra of both short
and long strings on the CFT and the string side match. The duality should be
understood as perturbative in $N^{-1}$.
