High resolution in situ EXAFS during temperature-programmed reduction was performed on CuZSM-5 to elucidate the state of copper under reaction conditions. Improvements in hardware and software allowed rapid acquisition of both XANES and EXAFS data during reduction, in particular, allowing observation of characteristic preedge features from various Cu oxidation states. EXAFS fitting and factor analysis of the normalized XANES edge were performed in an attempt to determine the number and type of Cu species present. The data suggests that initially only Cu2+ is present in two different locations on the zeolite; both states reduce to Cu1+ in both H-2 and CO, but under different conditions. Under H2 conditions, migration of Cu1+ to Cu-0 clusters is observed at 450 degreesC, while no metallic state is observed during CO reduction.