In my talk, I will present the energy-momentum method, intended for studying stability and bifurcation of Hamiltonian systems with symmetries. First, I shall introduce some fundamental notions from symplectic geometry such as Hamiltonian actions of Lie groups and momentum maps. In particular, I will briefly discuss the Marsden-Weinstein theorem, which allows for reducing Hamiltonian systems with a particular type of symmetries to Hamiltonian systems on certain quotient spaces. Then, I will explain the conditions on the stability of these reduced systems. Finally, I will present the energy-momentum method and briefly describe how it can be applied.