Addition reactions of pentafluorosulfur bromide (SF5Br) with fluoroolefins were studied. Three new adducts were prepared, SF5CHFCHC1Br, SF5CH2CH(CF3)Br, SF5CHFCFC1Br. SF5Br and CFC1=CHC1 yielded a small amount of product but attempts to add SF5Br to CF2=FCOF were unsuccessful. The mechanism for these addition reactions seems to involve a free radical addition pathway. Steric factors seem to be important in determining whether SF5Br will add to fluoroolefins. The new compounds, SF5CF(CF3)COF and SF5CF(CF3 )CONH2 have been produced from SF5CF=CF2. Analytical data, infrared, Raman, nmr and mass spectra are presented supporting the proposed structures for these new compounds.