The drive to develop Flat Panel Displays (FPD) on flexible substrates has been impeded by the permeability of plastic substrates to water vapor and oxygen which degrade the display medium or electrode materials. Recently, dielectric and ITO thin films barrier layers, separated by polymer layers, vacuum deposited on plastic sheets have demonstrated oxygen and water vapor transmission rates at or below the measurement limits of commercial instrumentation (0.005 cc/m@super 2@day and 0.005 gm/m@super 2@day). We report for the first time, ITO ultra-barriers with performance at or below this measurement limit, produced by vacuum roll to roll deposition. These ITO ultra-barriers, sputter deposited on plastic film substrates, have a typical visible transmittance of > 80% and a sheet resistance of < 20 ohms/square. Details of the deposition process, multilayer construction and measured performance are reported.