This study was conducted during the years of 2007, 2008 and 2009 in the Laboratory of the Department of Horticulture, Faculty of Agriculture, Suez CanalUniversity, Ismalia, Egypt.This experiment was carried out to study the effect of seed priming under low temperature on seed germination, seedling growth and chemical constituents of sweet corn. Seed priming of sweet corn seeds in mannitol or PEG at 25 ^oC recorded maximum values of germination percentage, fresh and dry weight/seedling and gave the tallest seedling, whereas seed priming in KNO₃ at 25 ^oC gave the earliest germination and more uniformity of germination in both seasons. Seed priming in KNO3 at 10 ^oC increased contents of total carbohydrate, total phenol and amylase enzyme in seedling, whereas seed priming in mannitol at 10 ^oC increased peroxidase enzyme.