Abstract: The UV photodissociation of UF6 excited in the B-X band is investigated with the 253.7 nm radiation from a filter Hg lamp. In the presence of H2, the dissociation yields are measured as a function of the incident light intensity, the partial pressure of hydrogen and various gas additives (Ar, N2 and SF6). The apparent quantum yield of 1.8±0.1 is observed for UF6-H2 system and of near unity for UF6-CO system. The UV photodissociation machanism of UF6 excited in the B-X band is discussed.