Copper-ethylenediamine (Cu-en) is produced by the reaction of laser-vaporized Cu atoms with en vapor and studied by pulsed-field ionization zero-electron kinetic energy (PFI-ZEKE) photoelectron spectroscopy and ab initio calculations. Four possible isomers are predicted for the complex, and a monodentate structure with an internal hydrogen bond is identified. For this hydrogen-bonded structure, the adiabatic ionization potential and frequencies of the Cu-en stretch, Cu-en bend, and hydrogen-bond stretch are measured from the PFI-ZEKE spectrum, and Cu-en dissociation energies are obtained from second-order Moller-Plesset (MP2) calculations.