PURPOSE: To evaluate the characteristic magnetic resonance imaging(MRI) findings of the wall of brain ab-scess,focusing on the signal intensity of T2-, proton density-weighted and FLAIR images. MATERIALS AND METHODS: MR images of 15 cases of brain abscess all proven by surgical pathology, were retro-spectively reviewed. The wall of each abscess was evaluated in terms of the presence or absence of dark signal intensity and layering, overall signal intensity of the abscess wall, and signal intensity of its innermost layer,including the border zone, as seen on T2-, proton density-weighted, and FLAIR images. The location of the ab-scess, extent of surrounding edema, and the presence of ring enhancement were also evaluated. RESULTS: On the three types of image, dark signal intensity within an abscess wall was noted in 11 cases (73% ) . Layers of alternating high and low signal intensity of abscess wall were noted in 13 cases (87 %). A rim of isoor high intensity(relative to the central necrotic portion) between the abscess wall of low-intensity rim and the outer part of the necrotic portion was seen on all three image types in 12 cases (80 %). The signal intensity of abscess wall, as seen on T1-weighted images, was slightly high in nine cases (60%) and iso-intense in six ( 40%). In 11 cases (73%), brain abscesses were located at the corticomedullary junction. The average diameter of abscesses was 4 cm, and ring enhancement of the abscess wall was noted in 14 cases (93%). Thirteen cases ( 87%) showed moderate to severe brain edema. CONCLUSION: Layering of alternating high and low signal intensity of abscess wall(87%) and an iso- or high sig-nal intensity rim between the low intensity rim of the abscess wall and outer necrotic portion(80%) were seen on T2-, proton density-weighted and FLAIR images. These MRI findings may be helpful in the diagnosis of brain abscess.