Two Higgs doublet extensions of the Standard Model predict the existence of charged Higgs bosons ( H^{+/-}). In such models  the branching  fraction for top quarks B(t->H^{+}b) can be large  thus  competing with the SM decay t->W^{+}b.

This study presents the results of a search of charged Higgs in the decay products of the pair-produced top quarks. This search is based on the cross section measurements of ttbar production in four exclusive decay channels; the "dilepton" , "lepton + jets" with exactly one tag, "lepton + jets" with two or more tags and "lepton + hadronic tau" channel.

Assuming the charged Higgs decays to csbar, taunu, t*b and Wh0,  limits in the  t->Hb branching ratio are obtained. The results are shown in the context of the MSSM.