In many clinical settings, nurses have a vital role in pain assessment and titration of opioid doses. Surveys of nurses have revealed knowledge deficits in these areas that are thought to contribute to under-treatment of pain. The present study surveys nurses' decisions about assessment and treatment of pain in 2 patient situations and confirms that nurses continue to undertreat severe pain. As shown in previous studies, nurses may be more influenced by the patient's behavior than the patient's self-report of pain, especially in relation to decisions about opioid titration. Nurses are less likely to increase a previously safe but ineffective dose of opioid for a smiling patient than a grimacing patient. Survey results reveal a tendency for nurses' personal opinions about the patients' pain, rather than their recorded assessments, to influence choice of opioid dose and to contribute to undertreatment of pain.