The spectrum of eight-times ionized iron, Fe ix, was studied in the 110–200 Å region. A low inductance vacuum spark and a 3 m grazing incidence spectrograph were used for the excitation and recording of the spectrum. Previous analyses of Fe ix have been greatly extended and partly revised. The number of known lines in the 3p 53d–3p 54f and 3p 53d–3p 43d 2 transition arrays is extended to 25 and 81, respectively. Most of the identifications of the Fe ix lines from the 3p 53d–3p 43d 2 transition array in the solar spectrum have been confirmed and several new identifications are suggested.