Two--loop heavy Higgs corrections to the Higgs fermionic width

We calculate the two–loop electroweak corrections to the fermionic decay width of the Higgs boson at leading order in $m_H$. The sum of one–loop and two–loop radiative corrections turns out to be at 6% level over the whole range of $m_H$ where the perturbation theory is supposed to be a sensible approximation. We show that the perturbative approach breaks down at $m_{H} \sim$ 1.4 TeV, and address the question of its relevance beyond this limit.