  We report the first observation of $B^{\pm}\to\psi(2S)\pi^{\pm}$, a Cabibbo-
and color-suppressed decay. This analysis is based on $657\times10^{6}$
$B\overline B$ events collected at the $\Upsilon(4S)$ resonance with the Belle
detector at the KEKB energy-asymmetric $e^+e^-$ collider. The measured
branching fraction is ($2.44 \pm 0.22 \pm 0.20$)$\times 10^{-5}$ and the charge
asymmetry is $\mathcal{A}=0.022 \pm 0.085 \pm 0.016$. The ratio of the
branching fractions $\mathcal {B}(B^{\pm} \to \psi(2S) \pi^{\pm})$$/ \mathcal
{B}(B^{\pm} \to \psi(2S) K^{\pm})$ $ = (3.99 \pm 0.36\pm 0.17)%$ is also
determined.
