Flaxoat nutty bar, a granola cereal bar was developed using oat and wheat as major cereal ingredients and their shelf life was assessed in polypropylene (PP 75 μ), paper (42 GSM) aluminium foil (20 μ) polyethylene (PFP, 37.5 μ) and metallised polyester (MP, 12 μ) low density/linear low density (150 μ) (with and without vacuum) films and stored under ambient temperature conditions and 37℃. Chemical changes in bar under different packaging materials during storage revealed that, the bar remained stable and acceptable for 12 months at ambient conditions irrespective of the packaging materials used, while at 37℃, the bar packed in PP films remained stable for 6 months only and rest of the bars packed in PFP, MP and MP (vacuum) films found stable and acceptable for the entire storage period of 12 months. The effect of a_w on lipid peroxidation established the maximum stability of the bar at 0.33 a_w. Fourteen fatty acids were identified in which oleic (50.91%), linoleic (22.50%) and palmitic (12.63%) acids were found to be the major fatty acids. Fortification of a bar with vitamin C, B₁ and B₂ contents to meet 50% RDA enhanced vitamin contents and the maximum retention was observed in bars packed under vacuum in MP films.