In the study included 45 patients randomized into three equal groups. Group D received 5 μg dexmedetomidine, group F received 25 μg fentanyl and group DF received 5 μg dexmedetomidine plus 25 μg fentanyl. These drugs were added to 2.5 ml hyperbaric bupivacaine 0.5% for all groups. intrathecal dexmedetomidine as an adjuvant to bupivacaine seems to be a good alternative to fentanyl for knee arthroscopy due to its intrathecal anesthetic and analgesic properties with minimal side effects. There is no need to add fentanyl to dexmedetomidine intrathecally; this combination was no better than dexmedetomidine alone in efficacy or safety.