Deuteron and anti-deuteron production in Z decays has been observed in the ALEPH experiment at LEP. The production rate of anti-deuterons is measured to be (5.9±1.8±0.5)×10−6 per hadronic Z decay in the anti-deuteron momentum range from 0.62 to 1.03 GeV/c. The coalescence parameter B2, which characterizes the likelihood of anti-deuteron production, is measured to be 0.0033±0.0013 GeV2 in Z decays. These measurements indicate that the production of anti-deuterons is suppressed in e+e− collisions compared to that in pp and photoproduction collisions.