The microwave spectrum of pentafluorosulfanylisocyanate, SF₅ -N = C = 0 has been investigated in the 8 GHz to 26 GHz region using a conventional Stark modulated spectrometer. Twenty six transitions have been assigned. A rigid rotor fit was performed by using low J transitions. The spectroscopic constants obtained are A = 2707.69 MHz, B = 1191.22 MHz, and C = 1191.13 MHz. These constants are close to those determined by the electron diffraction study on pentafluorosulfanylisocyanate and to this extent tend to support the bent -N = C = 0 structure as proposed by the electron diffraction study. / M.S.