Using the theory of planned behavior, the study aim was to determine the relationships among nurses’ beliefs, attitudes, perceived norms, perceived behavioral control, intentions, and behavior regarding pain management for hospitalized elderly patients with postoperative pain. A cross-sectional design was used with a convenience sample of 140 nurses working in adult surgical units at three hospitals. Based on path analyses, nurses’ behavioral, normative, and control beliefs, respectively, had direct effects on their attitudes, perceived norms, and perceived behavioral control regarding pain management. Nurses’ attitudes and perceived norms had direct effects on their pain management intentions. However, nurses’ intentions had no direct effect on their behavior (measured by responses to questions about case study vignettes). This study highlights the need for education that enhances nurses’ perceptions of pain management benefits, the influence of normative referents, and their ability to assess pain and administer pro re nata (PRN) opioid analgesics.