  We present measurements of time-dependent CP-violation asymmetries for the
decays B0 to eta'K0. The data sample corresponds to 347 million BBbar pairs
produced by e+e- annihilation at the Upsilon(4S) resonance in the PEP-II
collider, and collected with the BaBar detector. The preliminary results are S
= 0.55+/-0.11+/-0.002, and C = -0.15+/-0.07+/-0.03, where the first error
quoted is statistical, the second systematic.
