'As needed' non-nightly intake of hypnotic agents by patients suffering from chronic insomnia is likely to offer benefits such as maintained efficacy while preventing unnecessary long-term nightly use associated with the risk of tolerance and dependence. To date, three studies have proven the 'as needed' approach with zolpidem in patients with primary insomnia treated in outpatient practice. In total, more than 3000 primary care patients, proved that flexible or semi-flexible schedules of zolpidem 'as needed' treatment are feasible. In all the studies, 'as needed' zolpidem treatment was both effective and well tolerated by the patients. Moreover, the results of these studies clearly indicated that chronic insomniac patients are capable of limiting their hypnotic intake, showing no tendency to increase intake over time and even a trend to decreasing use of medication.