Onion seed cv. Giza 6 " Improved " was treated with priming in salicylic acid, fungicide vitavax and salicylic acid + fungicide vitavax before packing in cloth, aluminum foil and polyethylene bags for 0, 3, 6, 9 and 12 month, after treatment. Seed moisture content %, germination %, seed and seedling vigor traits and fungi infestation% were recorded after each storage period. Seed treatments maintained onion seed quality as measured by; seed germination%, tetrazolium test, seed vigor (germination% after accelerated aging test and electrical conductivity, seedling vigor (seedling length and seedling dry weight) and fungi infection% comparing untreated seeds. Type of seed packing materials significantly affected seed moisture content and quality traits of onion seed. Aluminum foil and polyethylene bags maintained onion seed at low moisture content, fungi infestation, high seed and seedling vigor comparing cloth bags. Prolong storage periods from 0 to 3, 6, 9 and 12 months decreased germination%, viable seed, accelerated aging test%, seedling vigor traits and fungi infestation%. Treating onion seed by salicylic acid solution, fungicide vitavax and salicylic acid solution+ fungicide vitavax before storage in aluminum foil or polyethylene bag maintained onion seed germination %, seed and seedling vigor comparing untreated seed stored in cloth bags. This study suggested that, onion seed should be treated by fungicide vitavax before storage in aluminum foil to maintain onion seed quality during storage and get high field emergence.