Indication for prescription was not available on pharmacy records. At Group Health in 2001–2003 we determined indication through ICD-9 codes recorded on visit encounters to the prescribing physician that occurred within 90 days of the initial prescription (N=151,314 episodes of opioid use). It was possible to link a preceding encounter within 90 days to an initial opioid prescription for 74.4% of the episodes. The most common diagnostic groups observed on the linked encounters were: extremity pain (13.4%); back pain (13.3%); fractures, contusions, injury (7.1%); abdominal pain/hernia (5.1%); osteoarthritis (3.8%); neck pain (3.6 %); headache (2.6 %); kidney stones/gall stones (1.9%); and menstrual/reproductive pain (1.0%).