  We review QCD sum rule applications to hadronic matrix elements of exclusive
$B$ and $D$ decays. Results are presented for the form factors $f^+$ and $F_0$
of $B \rightarrow \pi$ and $D\rightarrow \pi$ transitions. The predictions are
used to compute the width of $D^* \rightarrow D \pi$, and to extract the CKM
parameter $V_{ub}$ from the measured $B \rightarrow \pi e \nu$ width.
Furthermore, we comment on weak annihilation in $B \rightarrow \rho \gamma$, as
well as on the radiative decays $D \rightarrow \rho \gamma$, $D \rightarrow K^*
\gamma$, and $B \rightarrow \mu \nu \gamma$.
