Ferula gummosa is a monocarpic plant which is native to Iran. Drought was imposed by applying 0%, 5%, 10% and 15% concentrations of polyethylene glycol (PEG) 6000. Rate and percentage of seed germination decreased by drought stress. In the treatment of 15% was not observed seed germination. The mass of seedlings decreased under drought. Protein content was elevated at 5% PEG. The catalase activity increased under drought stress, while other antioxidant enzymes (peroxidase, polyphenol oxidase, superoxide dismutase and ascorbate peroxidase) presented progressive decrease in their activity at all PEG concentrations. These results indicate that the seed germination of Ferula is sensitive to drought.