This study was carried out to investigate the effect of muscle part and aging period on free amino acids andaroma compounds of Hanwoo (Korean cattle) cow beef. The M. longissimus (ML) and M. semitendinosus (MS)from 101 mon-old-cows were aged at 2℃ for 14 d. The free amino acids concentration increased in both MLand MS on 14 d of aging. In ML, asparagine, glutamine, histidine, glycine, threonine, arginine, tyrosine,phenylalanine, isoleucine, leucine and lysine were significantly (p<0.05) higher than those in MS. Varieties ofaldehydes, ketones, alcohols, hydrocarbons, nitrogen and sulfur compounds were detected in both ML and MSand majority of these compounds showed increasing trend on aging. The ML had higher 14 aldehydes(acetaldehyde, 2-methylpropanal, 3-methylbutanal, 2-methylbutanal, pentanal, hexanal, heptanal, E-2-heptanal,octanal, 2-octenal, 2-nonenal, E-2-decenal, E,E-2,4-decadienal and 2-undecenal), 5 ketones (2-propanone,2,3-butanedione, 2-butanone, 2-heptanone and 2,3-octanedione), 4 alcohols (ethanol, 1-pentanol, 1-hexanol and1-octanol), 3 hydrocarbons (3-ethyl-2-methyl-1,3-hexadiene, 3-methyldecane and 2,2-dimethyloctane) significantly(p<0.05) compared with MS. However, the MS had higher 5 nitrogen and sulfur compounds (methanethiol,dimethyldisulfide, fufural, 2,5-dimethylpyrazine and 2-octylfuran) significantly (p<0.05) compared with ML.