Study Objective: The application of regional anesthesia techniques as a component of multimodal analgesia in knee arthroscopic surgeries increases the quality of postoperative analgesia. Adductor canal block (ACB) is an effective “motor sparing” analgesia technique used in knee surgeries. In this study, we aimed to evaluate the efficacy of two different concentrations of local anesthetic mixtures in terms of postoperative analgesia in patients undergoing knee arthroscopic intervention compared to each other and the control group. Design: Prospective, randomized, controlled, blinded Setting: Tertiary hospital Patients: A total of 60 patients (ASA I-II) were evaluated in three groups, with 20 in each group. Interventions: Standardized postoperative analgesia was planned for all groups. In addition, ultrasound guided ACB (same volume / two different concentrations of bupivacaine-0.25% vs 0.16%) was applied to the experimental groups. Measurements: Tramadol consumption, rescue analgesic requirement and Numeric Rating Scores (NRS). Main Results: Tramadol requirement in the first 24 hours was significantly higher in the control group (209.5±23.27 mg),(p<0.001), and there was no difference between the experimental groups (63±42.06 mg vs 80.5±36.63 mg). Although the mean NRS score in the first three hours was higher in the control group than in both block groups, it was similar in all groups in the following measurements. Conclusion: In arthroscopic knee surgery, ACB interventions with 0.25% and 0.16% concentrations of bupivacaine were similar in terms of postoperative analgesic efficacy, and they increased the quality of multimodal analgesics more than the control group.