The decay-time-dependent CP asymmetry in B0→ D∗±D∓ decays is mea- sured using a data set corresponding to an integrated luminosity of 9 fb−1 recorded by the LHCb detector in proton-proton collisions at centre-of-mass energies of 7, 8 and 13 TeV. The CP parameters are measured asSD∗D=−0.861±0.077stat±0.019syst,ΔSD∗D=0.019±0.075stat±0.012syst,CD∗D=−0.059±0.092stat±0.020syst,ΔCD∗D=−0.031±0.092stat±0.016syst,AD∗D=0.008±0.014stat±0.006syst.\\documentclass[12pt]{minimal}\t\t\t\t\\usepackage{amsmath}\t\t\t\t\\usepackage{wasysym}\t\t\t\t\\usepackage{amsfonts}\t\t\t\t\\usepackage{amssymb}\t\t\t\t\\usepackage{amsbsy}\t\t\t\t\\usepackage{mathrsfs}\t\t\t\t\\usepackage{upgreek}\t\t\t\t\\setlength{\\oddsidemargin}{-69pt}\t\t\t\t\\begin{document}$$ {\\displaystyle \\begin{array}{c}{S}_{D\\ast D}=-0.861\\pm 0.077\\left(\\mathrm{stat}\\right)\\pm 0.019\\left(\\mathrm{syst}\\right),\\\\ {}\\varDelta {S}_{D\\ast D}=0.019\\pm 0.075\\left(\\mathrm{stat}\\right)\\pm 0.012\\left(\\mathrm{syst}\\right),\\\\ {}{C}_{D\\ast D}=-0.059\\pm 0.092\\left(\\mathrm{stat}\\right)\\pm 0.020\\left(\\mathrm{syst}\\right),\\\\ {}{\\varDelta C}_{D\\ast D}=-0.031\\pm 0.092\\left(\\mathrm{stat}\\right)\\pm 0.016\\left(\\mathrm{syst}\\right),\\\\ {}{\\mathcal{A}}_{D\\ast D}=\\kern0.75em 0.008\\pm 0.014\\left(\\mathrm{stat}\\right)\\pm 0.006\\left(\\mathrm{syst}\\right).\\end{array}} $$\\end{document}The analysis provides the most precise single measurement of CP violation in this decay channel to date. All parameters are consistent with their current world average values.