Purpose: This study was conducted to detect IL-6 in synovial fluid in cases with TMJ internal derangement. Patients & Methods: This study was conducted on forty patients ASA class I with TMJ Internal derangement. All patients had been subjected to arthrocentesis. The synovial fluid was collected before wash and lavage was done for the affected joint. Then, the selected patients were divided randomly into two equal groups, group I: consisted of 20 patients where arthrocentesis was performed for the affected joint followed by intraarticular injection of one ml, tramadol hydrochloride. Group II: consisted of 20 patients where arthrocentesis was performed for the affected joint followed by intraarticular injection of one ml. sodium hyaluronate. Another synovial fluid sample was aspirated after one month. The interlieukin-6 receptors in the aspirated synovial fluid were measured using humans IL-6 enzyme-linked immunosorbent assay. Results: IL-6 was detected in the synovial fluid of joints with internal derangement. During follow up assessment of IL-6, the maximum decrease in IL-6 level was in the patients of group I who subjected to arthrocentesis with tramadol injection, as the mean IL-6 was (4.93 ± 1.36) followed by the patients of group II who subjected to arthrocentesis with sodium hyaluronate injection where the mean IL-6 level was (6.88 ± 1.76). There were significant p-value = (P = 0.000). Conclusions: It had been concluded that the detection of IL-6 in the synovial fluid of joints with internal derangement considered an indicator for inflammatory reaction in the joint and also the efficacy of arthrocentesis with tramadol suggested its anti-inflammatory effect.