2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/45541We review the current status of the high order perturbative QCD evaluation of the hadronic decay rates of the Z and Higgs bosons. A systematic classification of the various types of QCD corrections to $O(α_s^2)$ and $O(α_s^3)$ is made and their numerical status is clarified.6 pages, LaTeX, To appear in the Proceedings of the XXXth Rencontres de Moriond, France, 1995High Energy Physics - Phenomenologytext