The effect of intravenous dexamethasone on the regression of sensory and motor block after isobaric bupivacaine spinal anesthesia is unknown. We conducted a prospective, double-blind, randomized controlled trial on 60 patients who received intravenously either placebo (group P) or 8-mg dexamethasone (group D) during the intrathecal injection of 12-mg isobaric bupivacaine 0.5%. Primary outcome was the time from bupivacaine injection to regression of 2 dermatomes in relation to the highest dermatome blocked by the spinal local anesthetic. Time to 2-dermatome regression was 85 minutes (74-96 minutes) in group P versus 87 minutes (76-98 minutes) in group D (P = .79).