OBJECTIVES: Benzodiazepines (BZDs) as anxiolytics, sedatives and hypnotics are frequently prescribed in daily medical practice worldwide and their abuse also becomes a target of public health measures. Because frequent attenders to emergence departments (EDs) sometimes display different psychological features, the utilization pattern of BZDs among this group of patients deserves investigations. METHODS: The data sources came from the historical claims datasets of 1,000,000-person cohort (LHID2005) in 2007, offered by the National Health Insurance Research Database in Taiwan. BZDs were defined as those drug items belonging to groups of N03AE, N05BA, N05CD and N05CF in the ATC (Anatomical Therapeutic Chemical) classification system. For each beneficiary, the annual numbers of visits to EDs of hospitals and ambulatory visits to practicing clinics and outpatient departments of hospitals (excluding visits to dentistry and traditional Chinese medicine) with BZDs prescriptions in 2007 were calculated. RESULTS: Among the valid 962,768 beneficiaries of the 1,000,000-person cohort, 157,865 (16.4%) patients (96,004 females and 61,861 males; mean age 52.0 ± 17.8 [SD] years) had received BZDs during ambulatory visits and 156,259 (16.2%) patients (76,644 females and 79,615 males; mean age 38.5 ± 23.5 [SD] years) had visited EDs in 2007. Among the 806,509 beneficiaries who did not visit EDs in 2007, only 14.5% (n = 116,554) had ever received BZDs at ambulatory visits during the year. In contrast, 26.4% (n = 41,311) of the ED attenders had received BZDs: the percentage rose from 22.6% in one-time ED attenders to 78.8% in those having more than 12 ED visits in a year. CONCLUSIONS: The use of BZDs was strongly associated with ED visits in Taiwan. Further stratified analyses are required to elucidate this phenomenon.