We studied genetic variation and the effect of processing conditions on functional constituents such as free amino acids (FAA) and vitamin E in barley grain and malt. Large varietal differences, as much as 2.5 times, in the contents of FAA and gamma-aminobutanoic acid (GABA), were observed in pasted whole grain flour. 'Hulless barley parental line No. 2' had the highest content of FAA (219 mg/100 g) and GABA (49.9 mg/100 g). Waxy malting barley 'Daikei HL9-2-6' had the highest vitamin E content (55.4 mg/kg), and alpha-tocotrienol was the major form of vitamin E in all the cultivars. FAA and GABA levels were significantly increased in the malts compared to those in the grain: 5.6 to 12. 9 times higher concentrations of FAA and 1.6 to 2.4 times higher concentrations of GABA. Both FAA and GABA levels increased in malting barley cultivars as a function of prolonged steeping periods and an air-rest treatment during malt processing.