Opioid analgesia is the primary pharmacologic intervention for managing pain. However, opioids can cause various adverse effects including pruritus, nausea, constipation, and sedation. Respiratory depression is the most fatal side effect. Therefore, cautious monitoring of respiratory status must be done after opioid administration. Here, we report a patient who suffered from respiratory depression with deep sedation and aspiration pneumonitis after intrathecal morphine administration.