  The evaluation of the hadronic contribution to the muon magnetic anomaly a_mu
is reviewed, including a new estimate using precise results on the pi+pi-
spectral function from the KLOE Collaboration. It is found that the KLOE data
confirm to some extent the previous e+e- annihilation data in this channel, and
accentuate the disagreement with the isospin-breaking-corrected spectral
function from tau- -> pi-pi0 nu decays. Correcting for the empirical difference
in the mass of the charged and the neutral rho locally improves, but does not
resolve this discrepancy. A preliminary reevaluation (including the KLOE data)
of the e+e- -based Standard Model prediction of a_mu results in a deviation of
2.7 standard deviations from the BNL measurement.
