This is a case report of pneuothorax which is the most specific complication of the supraclavicular brachial plexus block. This 19 year old patient underwent supraclavicular brachial plexus block with arm in abduction for stump revision of left thumb due to stump pain. When a pneuothorax was noted on the chest X-ray film on 37 hours after the block, closed thoracotomy with water-sealed drainage was done immediately. The pneuothorax dissipated 58 hours post-thoracotomy, therefore, chest tube was removed.