The photoelectron spectrum of the anilinide ion has been measured. The spectrum exhibits a vibrational progression of the CCC in-plane bending mode of the anilino radical in its electronic ground state. The observed fundamental frequency is 524 +/- 10 cm(-1). The electron affinity (EA) of the radical is determined to be 1.607 +/- 0.004 eV. The EA value is combined with the N-H bond dissociation energy of aniline in a negative ion thermochemical cycle to derive the deprotonation enthalpy of aniline at 0 K; Delta H-acid(0)(PhHN-H) = 1535.4 +/- 0.7 kJ mol(-1). Temperature corrections are made to obtain the corresponding value at 298 K and the gas-phase acidity; Delta H-acid(298)(PhHN-H) = 1540.8 +/- 1.0 kJ mol(-1) and Delta(acid)G(298)(PhHN-H) = 1509.2 +/- 1.5 kJ mol(-1), respectively. The compatibility of this value in the acidity scale that is currently available is examined by utilizing the acidity of acetaldehyde as a reference.