Background: Although intra-articular bupivacaine produces sufficient analgesia after knee arthroscopic surgery, but with short duration. So, the need to search for an adjuvant with longer duration of analgesia is preferable. Objectives: This study aimed to compare the duration of analgesia, total rescue analgesic consumptions, pain intensity, adverse effects and patients satisfaction of dexmedetomidine and fentanyl as adjuvants to intra-articular bupivacaine for analgesia after knee arthroscopy. Study Design: A prospective double-blind randomized controlled study. Setting:Academic University Hospitals. Methods: After ending arthroscopy and 10 minutes before deflation of tourniquet, forty-five patients were randomly allocated into three equal groups: Group B (n=15): received Intra-articular injection of 50mg (20 ml) bupivacaine 0.25%+ 1 ml saline, group BD (n=15): received intra-articular injection 20 ml bupivacaine 0.25% plus 100ug (1mL) dexmedetomidine and group BF (n=15): received Intra-articular injection 20 ml bupivacaine 0.25% plus 50 ug (1mL) fentanyl. Result(s): BF group had statistically significant longest duration of analgesia (693.3±22.6min) compared to group BD (505.8±23.5min) and group B (244.1±17.5min) (p<0.0001). The total pethidine consumption was statistically significantly decreased in group BF (35±12.6mg) compared to BD and B groups (60±12.6 and 83.3±15.4mg) respectively (p<0.0001). Group BF and BD showed highly statistically significant lower postoperative static and dynamic pain scores at 30min, 1, 2, 4 and 6 hours compared to group B. However, group BF was comparable to group BD at the same time intervals. Postoperative static and dynamic pain scores showed highly statistically significant higher values at (4 hours in group B, 8 hours in group BD and 12 hours in group BF) (p<0.0001). No significant side-effects observed among groups. Duration of analgesia was the most important parameter that determined patient satisfaction. Limitations:small sample size and lack of studies that compare between both adjuvants