In this talk I will review the status of the extraction of the Standard Model parameter Vud from nuclear beta decays, which provides a powerful tool to search for new physics. Particular emphasis is put on the recent developments of the weak decay form factors, electroweak radiative corrections, and the isospin-symmetry-breaking correction to the Fermi matrix element. I will show how lattice QCD, nuclear ab-initio theory and experiments pave the way for the extraction of Vud at a 0.01% precision.