The National Comprehensive Cancer Network (NCCN), an organization of 19 of the world's leading cancer centers, developed and communicated a cancer pain treatment guideline. NCCN seeks to implement guidelines through performance measurement using a NCCN Oncology Outcomes Database. This is a preliminary report from the NCCN Cancer Pain Management Database Project. The primary objective of this NCCN Cancer Pain Management Database Project study is to evaluate the frequency, methods, and extent of documentation of cancer pain assessment and managementat NCCN institutions. A pain data dictionary and related data collection forms were first developed. The records of 209 breast cancer patients with bone metastases were then studied. The frequency of pain mentions, type of pain assessment tool used, pain characteristics, type of clinician documenting pain, location in the medical record, and pain treatment characteristics were noted. The majority of clinical encounters included pain mentions, although considerable variability was found in pain documentation between providers and between inpatient and outpatient settings. Nurses more frequently recorded pain, usually as a numeric pain intensity score. Pain specialists were more likely to record a complete description of pain. A significant minority of patients experienced moderate to severe pain. In a small subgroup of patients with moderate to severe pain, pain treatment was not recorded. The undertreatment of cancer pain has been a focus of investigation and review for the past two decades. Quality improvement efforts to raise the standard of pain management have been underway. The results of this study highlight the need for standardization of pain documentation in comprehensive cancer centers as a prerequisite for the proper assessment of cancer pain and the improvement of clinical outcomes of pain management.