  We present the first measurement of the form factor ratios g1/f1 (direct
axial-vector to vector), g2/f1 (second class current) and f2/f1 (weak
magnetism) for the decay Xi0 -> Sigma+ e- anti-nu/e using the KTeV (E799) beam
line and detector at Fermilab. From the Sigma+ polarization measured with the
decay Sigma+ -> p pi0 and the e- - anti-nu/e correlation, we measure g1/f1 to
be 1.32 +0.21-0.17(stat.) +/- 0.05(syst.), assuming the SU(3)f (flavor) values
for g2/f1 and f2/f1. Our results are all consistent with exact SU(3)f symmetry.
