This study documents the use of oral and transdermal opioids among patients with metastatic cancer during their final year of life. Using a large, integrated health-insurance claims database, we identified all patients who had metastatic lung, breast, colorectal, prostate, or breast cancer and who also died in 1998 or 1999. We then examined all pharmacy claims for these patients over their final 12 months of life. A total of 2,132 patients were identified who met study entrance criteria. Among patients with bone metastases (n=717), 86.9% received opioids at some point during their final year of life; 71.2% of those without bone metastases (n=1,415) received them. Corresponding figures for long-acting opioids were 52.9% and 23.5%. Coverage ratios (total days supplied/total noninstitutionalized days) for any opioids and long-acting opioids were 25.1% and 12.5%, respectively, among patients with bone metastases, and 13.9% and 4.2% for those without bone metastases. During the final month of life, these ratios were 50.8% and 31.3%, and 28.7% and 13.1%. These relatively low rates of opioid use among patients with metastatic cancer in their final year of life suggest that pain in many cases may be suboptimally treated.