  We evaluate pionic decay widths of Lambda hypernuclei using a shell model
for, both the nuclear bound and the continuum nucleon wave functions in the
final state, and distorted waves for the outgoing pion. An excellent agreement
with the recent KEK measurement of $\pi^-$-decay widths of $^{12}_\Lambda$C and
$^{28}_\Lambda$Si is found. Besides, results for
  $^{56}_\Lambda$Fe are consistent with the existing upper bound.
