The photoelectron spectra of FeC2- and FeC2(D)(-) are studied at 3.49 eV photon energy. The electron affinities of FeC2 and FeC2H(D) are determined to be 1.91(10) and 1.41(5) eV, respectively. An excited state of FeC2 at 1 eV above its ground state is also observed. Only one major detachment channel is observed for FeC2H(D)(-). A vibrationally resolved spectrum at 2.33 eV photon energy for FeC2D- is also obtained with a Fe-C stretching progression, yielding a vibrational frequency of 500(100) cm(-1). The spectra provide unique information on the bonding between Fe and C-2 and C2H(D).