In this paper, we present experimental and numerical analysis on Extraordinary Optical Transmission (EOT) through various nano-hole arrays in a thick metal film within the visible and near infra-red spectrum of light. Large nano-hole arrays with different spacing between adjacent holes in the square lattice arrangement were fabricated using Electron Beam Lithography (EBL). Optical transmission properties (wavelength, peak, and spectral bandwidth of transmission resonances) of the fabricated nano-hole arrays were characterized and validated by numerical analysis based on Finite Difference Time Domain (FDTD). Finally, the dependencies and discrepancies between EOT properties of various nanohole arrays were analyzed.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.