Local mixing dynamics was recently investigated experimentally in Taylor-Couette single-phase flow, thanks to simultaneous Particle Image Velocimetry (PIV) and Planar Laser-Induced Fluorescence (PLIF) techniques. The results highlighted the influence of the successive flow bifurcations and the role of azimuthal wave states on the dispersion of dye injected in Taylor-Couette flows. The present work extends this study to two-phase configurations with spherical solid particles. The respective effect of particle size and concentration on the vortices size and transition thresholds between the various flow regimes has been examined thanks to flow visualizations and PIV measurements. These hydrodynamic features have been complemented with PLIF experiments, that revealed a drastic enhancement of mixing due to the presence of particles regardless of the flow regime, highlighting the existence of significant particle-induced mixing in Taylor-Couette flows. (C) 2016 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.