Abstract Background: Arthrocentesis is an effective treatment modality for temporomandibular disorders, especially in patients who have pain and limited mouth opening. Surgeons generally suggest theraputic exercises after arthrocentesis and arthroscopy procedures. Aim of Study: This study investigated whether immediate physical exercises after arthrocentesis would result in early improvements in clinical symptoms in patients with temporo-mandibular joint disc displacement without reduction (TMJ DDw/oR). Patients and Methods: The study group was composed of 30 patients with TMJ DDw/oR. Patients who needed arthrocentesis after failed conservative nonsurgical treatment were enrolled in the study. The study was done in the Depart-ment of Oral and Maxillofacial Surgery, Hospital of Oral & Dental Medicine, Cairo University from March 2018 – March 2019. Informed written consent was obtained from all partic-ipants. The patients were randomly classified into 2 groups of equal number. - Group 1 was composed of 15 patients who were started on an immediate physiotherapy program after the arthrocentesis procedure. - Group 2 was composed of 15 patients who were not started on a physiotherapy program after the arthrocentesis proce-dure. Physiotherapy included a 4-week exercise program. Pa-tients were followed for 3 months. Range of maximal mouth opening (MMO) and joint pain as measured by the visual analog scale (VAS) were examined to determine clinical efficacy before and after treatment. Results: There was a statistical increase in group A (study group) in comparison to group B (control group) with MMO (pretreatment, after 4 weeks and after 3 months). There was a statistically significant decrease in group A (study group) in comparison to group (B control group) with VAS (pretreatment, after 4 weeks and after 3 months arthro-centesis has a significant effect on the range of mouth opening and pain decrease. Conclusion: Immediate Physical exercise after arthrocen-tesis has a significant effect on the range of mouth opening and does decrease pain.