The electron states of copper have been studied by ESR and UV-Vis as a function of the method used for preparation of Cu-ZSM-5 (ion-exchange, wet impregnation, and deposition), synthesis conditions (pH of copper solution, copper precursor, temperature, etc.) and copper loading.For calcined Cu-ZSM-5 samples treated under vacuum at 400 o C, axial ESR spectra of O - ion radicals (g =2.05, g =2.02), which are presumably assigned to linear O - Cu + O - Cu + O - -chains in zeolite channels, are observed. The same samples treated under vacuum at 150-400 o C, exhibit UV-Vis absorption bands at the unexpected region of 18,000-23,000cm - 1 . They are assigned to the ligand-metal charge transfer bands in O 2 - Cu 2 + O 2 - Cu 2 + O 2 - -like chains in the zeolite channels. Along with these states, isolated octahedral Cu 2 + ions with different extents of tetragonal distortion (absorption band (a.b.) 12,500-14,000cm - 1 ) and clustered copper oxide species (charge transfer band (CTB) 27,000-32,000cm - 1 ) are also observed.