The development of high barrier food packaging materials employing novel polymer processing methods is being conducted by the U.S. Army, under the Department of Defense Combat Feeding Research, Development and Engineering Program (CFREP). Research conducted under the project, “Alternative Polymer Processing Technologies” is investigating the effect of machine direction orientation (MDO) on the barrier, mechanical, and thermal properties of several high barrier multilayer films, which are targeted for use in military ration packaging. The multilayer films incorporate a core layer consisting of a specialty grade of high oxygen barrier ethylene co-vinyl alcohol (EVOH), and skin layers comprised of various polyolefin materials for added water vapor barrier, including an ultra high moisture barrier high density polyethylene (HDPE). A series of multilayer films were stretched at increasing ratios in the machine direction, and underwent testing and analysis before and after the orientation process. Processing was first conducted on a laboratory-scale batch type MDO unit, where 4 x 4 inch samples were individually oriented at a 4:1 stretch ratio. Films that showed the highest compatibility with the orientation process and displayed optimal mechanical and barrier properties were selected for the scaled-up, in-line MDO process, where films were oriented at 4:1, 5:1, and 6:1 stretch ratios. This in-line process more closely resembles a manufacturing-scale process and provided the opportunity to determine how processability and film properties are affected at higher production rates. In addition, this processing method allowed for orientation at high stretch ratios, which have been shown to further improve properties. Overall film quality and appearance was better with the in-line processing method, however properties for films oriented using both batch and in-line processing methods were comparable to one another, with respect to mechanical and oxygen barrier performance. For both processing methods a four to five fold increase in tensile strength, when tested in the machine direction (MD), was apparent in films after orientation, and a 75% increase Young’s modulus (MD) was also observed. Oxygen permeability was reduced by 40-50%, with the higher stretch ratios (6:1) of the in-line processing method resulting in the greatest overall reduction in oxygen permeability. Water vapor permeability increased after orientation employing the batch method, however it was shown to decrease or remain constant for films undergoing in-line processing. Thermal analysis by way of differential scanning calorimetry is underway to determine thermal transitions and enthalpy values that may correlate with the barrier data trends. Overall, this study has shown that scale-up from batch to in-line MDO produced films with comparable properties, however film quality and optimal property improvements were seen when the in-line process was employed.