PURPOSE: To correlate MR findings of amount of temporomandibular joint effusion with joint pain and disk displacement. MATERIALS AND METHODS: In 57 patients, 114 temporomandibular joints with symptoms of disorder(presence of clinical pain) were imaged. Closed and open mouth sagittal spin echo (SE) T1-weighted images (WI) and fast spin echo (FSE) T2-WI were obtained. We classified the amount of joint effusion into grades. Joint effusion was classified as either Grade I, II or III, as follours : in sagittal FSE T2-WI, a long diameter of joint effusion shorter than 1/3 of the diameter of the convex margin of temporal eminence was grade I; longer than 2/3 was grade III; between grade I and III was grade II. Disk displacement was classified as either with or without reduction in the open mouth position. These findings were correlated with one another and statistically analyzed. RESULTS: In 29 cases with joint pain (37%) and in 34 cases without pain (63%) there was no evidence of joint effusion; there were, however, more grade I joint effusion cases with pain (14 ; 60.9%) than without pain (9 : 39.1%). Cases of joint pain increased in proportion to grade of joint effusion, which was statistically significant (p<0.05). In joints without disk displacement, the largest grouping was that which showed no effusion (39 ; 72.2%) ; no joints showed grade III effusion. Cases of joint effusion decreased in proportion to grade of effusion. In joints with disk displacement, cases of joint effusion tended to increase in proportion to the grade of effusion. CONCLUSION: MR findings of amount of temporomandibular joint effusion correlate with joint pain and anterior disk displacement.