<p class="abstract"><strong>Background:</strong> <span lang="EN-IN">Supraclavicular brachial plexus block is widely used for surgery below shoulder joint. Adding adjuvant to local anesthetic drugs enhance the duration of block as well as postoperative analgesia. Dexamethasone very potent glucocorticoid when added to local significantly prolongs the duration of analgesia</span>.</p><p class="abstract"><strong>Methods:</strong> <span lang="EN-IN">This randomized, single blind, controlled study include 100 patients of either sex, aged 18–60 years, ASA status I–III, undergoing upper limb surgery were randomly allocated to receive either 0.375% 30 cc bupivacaine with 2 ml normal saline (group C, n=50) or 0.375% bupivacaine with 2 ml (8 mg) dexamethasone (group D, n=50). The observed parameters include onset and duration of motor and sensory block, duration of effective analgesia any side effects and hemodynamic (pulse rate, NIBP, SpO2). </span><span lang="EN-IN"> </span></p><p class="abstract"><strong>Results:</strong> <span lang="EN-IN">Mean onset time of sensory and motor block in group C was significantly longer as compared to group D. (p&lt;0.0001) The duration of sensory and motor blockade was significantly prolonged in group D compared to group C. (p&lt;0.0001) The duration of effective analgesia was also significantly prolonged in group D (931.2±69.88 mins) compared to group C (454.8±34.47 mins) (p&lt;0.0001)</span>.</p><p class="abstract"><strong>Conclusions:</strong> <span lang="EN-IN">Addition of dexamethasone to 0.375% bupivacaine in brachial plexus block speeds the onset and prolongs the duration of sensory and motor blockade. It also prolongs the duration of effective analgesia. </span></p>