  The Cabibbo suppressed decays $D\to Vl^+l^-$ (V is light vector meson)
present in principle the opportunity to observe the short distance FCNC
transition $c\to ul^+l^-$, which is sensitive to physics beyond the Standard
Model. We analyze these as well as the Cabibbo allowed $D \to V l^+ l^-$ decays
within the Standard Model, where in addition to the short distance dynamics
also the long distance dynamics is present. The long distance contribution is
induced by the effective nonleptonic weak Lagrangian accompanied by the
emission of a virtual photon, which occurs resonantly via conversion from a
vector meson $\rho^0, \omega$ or $\phi$ or nonresonantly as direct emission
from a $D$ meson. We calculate the branching ratios for all $D\to Vl^+l^-$
decays using the model, which combines heavy quark symmetry and chiral
perturbation theory. The short distance contribution due to $c\to ul^+l^-$
transition, which is present only in the Cabibbo suppressed decays, is found to
be three orders of magnitude smaller than the long distance contribution. The
branching ratios well above $10^{-7}$ for Cabibbo suppressed decays could
signal new physics. The most frequent decays are the Cabibbo allowed decays,
which are expected at the rates, that are not much lower than the present
experimental upper limit: $D_s^+\to \rho^+\mu^+\mu^-$ is expected at the
branching ratio of approximately $3\cdot 10^{-5}$, while $D^0\to\bar
K^{*0}\mu^+\mu^-$ is expected at $1.7\cdot 10^{-6}$.
