Opioid analgesics are the cornerstone of management for malignant pain. Their use in managing chronic, nonmalignant pain, albeit controversial, has increased in recent years. The decisions about whether to initiate opioid therapy or continue it over time should be guided by a comprehensive patient assessment. During long-term treatment, this assessment should focus on a broad range of outcomes, each of which should be documented in the medical record. The goal of this study was to develop an instrument, the Pain Assessment and Documentation Tool (PADT), to focus on key outcomes and provide a consistent way to document progress in pain management therapy over time. Items that assess 4 domains (pain relief, patient functioning, adverse events, and drug-related behaviors) were generated with input from a MEDLINE literature search and experts in pain and addiction management. The original tool was field tested by clinicians who applied it to the assessment of patients receiving long-term opioid therapy for the management of chronic, nonmalignant pain. Data analysis and debriefing telephone interviews with a formalized set of questions were then used to rephrase, delete, and refine items to create the final tool. A 6-member expert panel contributed to the initial development of the PADT. Twenty-seven clinicians completed the preliminary version of PADT for 388 patients. The original 59-item tool was modified to create a 41-item tool. The revised PADT was formatted for use as a chart note designed to assist clinicians in assessing and documenting 4 main outcome domains during long-term opioid use. In this study, the PADT appeared to be a useful tool for clinicians to guide the evaluation of several important outcomes during opioid therapy and provide a simple means of documenting patient care.