An efficient cobalt-tertiary-amine-mediated peroxy-trifluoromethylation and halodifluoromethylation of alkenes with simple and inexpensive CF2XBr (X = F, Cl, Br) has been described. This method demonstrated broad substrate scope and good to high yields with the tolerance of mono-, di-, and trisubstituted alkenes with both electron-donating and electron-withdrawing groups. The protocol provides an efficient access to various β-peroxyl trifluoromethyl/halodifluoromethyl derivatives. Further transformation of these type of compounds to other useful molecules, such as ketene aminal, α-trifluoromethyl ketone, and gem-difluoroalkene demonstrated the utility of this methodology.