The effects of quality grade (which reflects relative marbling) on the chemical, physical and sensory properties was investigated using Korean native cattle (Hanwoo) beef. Thirty-six Hanwoo cows were slaughtered and the carcasses were graded at 24h postmortem according to the Korean carcass grading system. The quality grade 1 (high quality), grade 2 and grade 3 (low quality) were based on the marbling score of longissimus dorsi (LD) muscles. The effects of quality grade on the meat quality parameters of beef LD muscle were assessed during aging. Loin-eye area, fat thickness and yield grade were all similar for the three quality groups. Mean lean color, fat color and maturity scores did not differ among quality grade groups (P>0.05). pH, Sarcomere length, WHC, collagen content, cooking loss, shear force and MFI were not affected by quality grade groups. Drip loss for grade 1 group was significantly lower than that for grade 3 groups (P