Anion femtosecond photoelectron spectroscopy (FPES) has been used to monitor intramolecular electronic relaxation dynamics following the excitation of the (C) over tilde (2)Pi (g)<--(X) over tilde (2)Pi (u) 0(0)(0) electronic transition in C-6(-). The time-dependent photoelectron spectra provide a detailed picture of the relaxation dynamics in which the initially excited (C) over tilde (2)Pi (g) (v=0) level evolves into highly vibrationally excited C-6(-) in its ground electronic state. The spectra show evidence for a two-step relaxation mechanism: internal conversion (IC) to vibrationally excited (B) over tilde (2)Sigma (+)(u) and (A) over tilde (2)Sigma (+)(g) states, occurring on a time scale of 730 +/- 50 fs, followed by IC from these intermediate states to highly vibrationally excited levels in the (X) over tilde (2)Pi (u) ground state with a time constant of 3.0 +/-0.1 ps.