Intrathecal opioids are routinely administered during spinal anesthesia for postcesarean analgesia. The effectiveness of intrathecal morphine for postcesarean analgesia is well established, and the use of intrathecal hydromorphone is growing. No prospective studies have compared the effectiveness of equipotent doses of intrathecal morphine versus intrathecal hydromorphone as part of a multimodal analgesic regimen for postcesarean analgesia. The authors hypothesized that intrathecal morphine would result in superior analgesia compared with intrathecal hydromorphone 24 h after delivery.