  We report the first observation of color-suppressed $\overline{B}^0\to D^0
\pi^0$ and $D^{(*)0} \omega$ decays and evidence of $\overline{B}^0 \to D^{*0}
\pi^0$ and $D^{(*)0} \eta$. The branching fractions are found to be ${\cal B}
(\overline{B}^0\to D^0 \pi^0) = (2.9 ^{+0.4}_{-0.3} \pm 0.6) \times 10^{-4}$,
${\cal B} (\overline{B}^0 \to D^0 \omega) = (1.7 ^{+0.5 +0.3}_{-0.4 -0.4})
\times 10^{-4}$, and ${\cal B} (\overline{B}^0 \to D^{*0} \omega) = (3.4
^{+1.3}_{-1.1}\pm 0.8) \times 10^{-4}$. The analysis is based on a data sample
of 21.3 fb$^{-1}$ collected at the $\Upsilon(4S)$ resonance by the Belle
detector at the KEKB $e^{+} e^{-}$ collider.
