STUDY OBJECTIVE: To examine recent national trends in outpatient visits for sleep related difficulties in the United States and prescriptions for sleep medications. DESIGN: Trend analysis. SETTING: Data from the National Ambulatory Medical Care Survey from 1999 to 2010. PARTICIPANTS: Patients age 20 y or older. MEASUREMENTS AND RESULTS: The number of office visits with insomnia as the stated reason for visit increased from 4.9 million visits in 1999 to 5.5 million visits in 2010 (13% increase), whereas the number with any sleep disturbance ranged from 6,394,000 visits in 1999 to 8,237,000 visits in 2010 (29% increase). The number of office visits for which a diagnosis of sleep apnea was recorded increased from 1.1 million visits in 1999 to 5.8 million visits in 2010 (442% increase), whereas the number of office visits for which any sleep related diagnosis was recorded ranged from 3.3 million visits in 1999 to 12.1 million visits in 2010 (266% increase). The number of prescriptions for any sleep medication ranged from 5.3 in 1999 to 20.8 million in 2010 (293% increase). Strong increases in the percentage of office visits resulting in a prescription for nonbenzodiazepine sleep medications (∼350%), benzodiazepine receptor agonists (∼430%), and any sleep medication (∼200%) were noted. CONCLUSIONS: Striking increases in the number and percentage of office visits for sleep related problems and in the number and percentage of office visits accompanied by a prescription for a sleep medication occurred from 1999-2010. CITATION: Ford ES, Wheaton AG, Cunningham TJ, Giles WH, Chapman DP, Croft JB. Trends in outpatient visits for insomnia, sleep apnea, and prescriptions for sleep medications among US adults: findings from the National Ambulatory Medical Care Survey 1999-2010.