  We report the observation of B0bar --> D0 eta' and the first observation of
B0bar --> D*0 eta', using 140 fb-1 of data collected at the Upsilon(4S)
resonance with the Belle detector at the KEKB asymmetric energy e+ e- collider.
We find the branching fractions to be B(B0bar --> D0 eta') = [ 1.14 +-
0.20(stat) +0.10-0.13(syst)] x 10^-4 and B(B0bar --> D*0 eta') = [ 1.21 +-
0.34(stat) +- 0.22(syst)] x 10^-4 with significances including systematic
uncertainty of 8.9 and 5.3 standard deviations, respectively.
