The latest results on several weak hadronic amplitudes that have been computed in numerical simulations are reviewed. Many of these results have already had, or are expected to have, a significant impact on the phenomenology of weak interactions, and in particular on our understanding ofCP violation. The main topics discussed in this review are: leptonic decay constants of pseudoscalar heavy-light mesons, B-\(\bar B\) mixing amplitudes, semi-leptonic decays of D and B mesons, radiative decays of B mesons and the Isgur-Wise function.