We investigate several phenomena related to FCNCs in the text {3-3-1-1} model. The sources of FCNCs at the tree-level from both the gauge and Higgs sectors are clarified. Experiments on the oscillation of mesons most stringently constrain the tree-level FCNCs. The lower bound on the new physics scale is imposed more tightly than in the previous, text {M}_{text {new}}>12 TeV. Under this bound, the tree-level FCNCs make a negligible contribution to the text {Br}(B_s rightarrow mu ^+ mu ^-), text {Br}(B rightarrow K^{*} mu ^+ mu ^-) and text {Br}(B^{+}rightarrow K^{+}mu ^{+}mu ^{-}). The branching ratio of radiative decay b rightarrow s gamma is enhanced by the ratio frac{v}{u} via diagrams with the charged Higgs mediation. In contrast, the charged currents of new gauge bosons significantly contribute to the decay process mu rightarrow e gamma .