The negative ion zero electron kinetic energy (ZEKE) spectrum of I-.CH3I is presented and discussed. In addition to the high-frequency vibrational structure previously seen in the photoelectron spectrum (PES) of I-.CH3I, the ZEKE spectrum reveals low-frequency vibrational structure due to excitation in two van der Waals modes in the ground (X) state of the neutral I.CH3I complex. Of the two other excited states of the neutral complex, the I state is not distinctly observed, and no vibrational structure due to van der Waals motion is observed for the II state.