To cope with increasing importance of water stress in food crop production, characteristics and cultivar differences in physiological responses of winter barley plants to water stress during seedling stage were studied employing three covered-barley, Milyang 12, Durubori, and Olbori, one naked-barley, Baekdong, and one two-row beer-barley, Hyangmaeg. Water stress was given to barley plants by withholding watering in soil-culture pots or by adding P.E.G. (polyethylene glycol, M.W. 4,000) to the nutrient culture solution. When water stress was imposed by withholding watering for 10 days to the seedlings grown in pot-soil for 10 days after emergence, leaf water potential of 5 cultivars was decreased almost to the same degree, from control -3.5 bar to the water stressed - 26.6 bar. However, growth and some physiological responses were differently affected by cultivars: The plant height was decreased by 16~26% ; seedling dry weight by 25~42% ; chlorophyll content by 21 ~39% ; second leaf survival rate by 8~18% ; and free proline content per gram of leaf dry weight was increased from control 0.2~0.5mg to the water stressed 5.8~13.2mg. Drought resistances of 5 barley cultivars, based on the leaf survival rate and the decreased rate in seedling dry weight at the end of stress treatment, were high in the order of 3 covered-barley>naked-barley>two-row barley.