We present measurements of decay amplitudes and triple-product correlations in B→K* decays based on 253fb-1 of data recorded at the Υ(4S) resonance with the Belle detector at the KEKB e+e- storage ring. The decay amplitudes for the three different helicity states are determined from the angular distributions of final-state particles. The longitudinal polarization amplitudes are found to be 0.45±0.05±0.02 for B0→K0 and 0.52±0.08±0.03 for B+→K+ decays. CP- and T-odd CP-violating triple-product asymmetries are measured to be consistent with zero. © 2005 The American Physical Society.