We describe age and gender trends in long-term use of prescribed opioids for chronic noncancer pain in 2 large health plans. Age- and gender-standardized incident (beginning in each year) and prevalent (ongoing) opioid use episodes were estimated with automated health care data from 1997 to 2005. Profiles of opioid use in 2005 by age and gender were also compared. From 1997 to 2005, age-gender groups exhibited a total percentage increase ranging from 16% to 87% for incident long-term opioid use and from 61% to 135% for prevalent long-term opioid use. Women had higher opioid use than did men. Older women had the highest prevalence of long-term opioid use (8%-9% in 2005). Concurrent use of sedative-hypnotic drugs and opioids was common, particularly among women. Risks and benefits of long-term opioid use are poorly understood, particularly among older adults. Increased surveillance of the safety of long-term opioid use is needed in community practice settings.