Photodecomposition of K-shell excited CF 3 SF 5 was investigated by means of photoelectron–photoion coincidence (PEPICO) and photoion–photoion coincidence (PIPICO) spectroscopy. In PEPICO mode to study site-selective fragmentation, the yield of CF3+ was high at the C1s→σCS∗ excitation and that of SF3+ was considerable at the excitation into σCF∗. When the F K-shell of SF 5 was selectively excited, the formation of CF3+ was prominent. The atomic ions of S + and F + were overwhelmingly produced with some amounts of S 2+ and S 3+ ions at the S K-shell excitation. Formation of highly charged CF3SF5n+(n=2–4) ions was confirmed by PIPICO spectroscopy. The yields of CF3SF5n+(n=3,4) were low at the S1s→σSF∗ excitation. Breakdown pathways of the CF3SF5n+ ions were discussed.