Bose-Einstein correlations between pairs of like-sign charged particles produced in e+e- annihilations near the Z0 peak have been studied using data taken with the DELPHI detector at LEP. An enhancement is found in the production of pairs of identical pions of similar momenta, with respect to a reference sample. Under the hypothesis that the pions are emitted by a spherically symmetrical source with gaussian density, the data indicate a radius of the source of r = 0.62 +/- 0.04(stat.) +/- 0.20(syst.) fm. The large systematic uncertainty reflects the sensitivity of r to the choice of the reference sample.
