Electroweak Corrections to the Supersymmetric Charged Higgs Fermionic Decay

One-loop radiative corrections to the charged Higgs coupling to two fermions and to the charged Higgs fermionic decay are studied. A renormalization scheme is proposed including the definition of the parameter $\tan\beta$ through the coupling of the CP-odd Higgs boson to a charged lepton pair. Loops including top and bottom quarks and squarks are considered using the unitary gauge. Large corrections to the coupling are found when there is a substantial mixing in the squark mass matrix, but these corrections are suprress in the decay rate. Interesting applications to rare processes are discussed.