  We observed Bose-Einstein correlation in pi0 pairs produced in Z0 decays
using the data sample collected by the OPAL detector at LEP 1 from 1991 to
1995. Using a static Gaussian picture for the pion emitter source, we obtain
the chaoticity parameter lambda = 0.55 +- 0.10 +- 0.10 and the source radius R
= (0.59 +- 0.08 +- 0.05) fm. according to the JETSET and HERWIG Monte Carlo
models, the Bose-Einstein correlations in our data sample largely connect pi0s
originating from the decays of different hadrons. Prompt pions formed at string
break-up of cluster decays only form a small fraction of the sample.
