This study was carried out to investigate aroma patterns of Hanwoo (Korean cattle) beef by using an Electronic nose. The M. longissimus muscle and Semimembranosus muscle after 24 hours postmortem was obtained, and half muscles cooked in water batch until internal temperature arrived at 70℃ or microwave for 30 sec. The raw and cooked beef samples stored at 1℃ for 11 days. Sensitivity values (dR/RO) among electronic nose data were changed differently by muscle parts, heat treatments and storage days. The dR/RO values from SY/LG, T30/1, P10/1, P10/2 were decreased at 11th storage compared with those at 1th storage. Mapping these data by using PCA (principal component analysis) showed that raw and cooked beef data were presented on the right and left side of board, respectively. The data of 1st storage were presented on the right side, and flock together. Otherwise, the data of 11th storage were spreaded out more widely on the left side. Consequently, the dR/RO value and PCA mapping by Electronic nose data showed difference by sample treatments and storage days. Therefore it will be possible to able to detect separated aroma patterns of Hanwoo beef by using an Electronic nose.