Aims: Benzodiazepines (BZDs) are effective in the short term against anxiety and insomnia. However, some BZD users develop BZD dependence after a relatively short period of time. Therefore, we aimed to identify the risk factors of BZD dependence. Design: An observational cohort study. Setting: The Netherlands. Participants: Four hundred and one BZD users of the 2981 participants of the Netherlands Study of Depression and Anxiety (NESDA) were included. Measurements: Socio-demographic, physical, psychological, addiction-related and BZD use-related characteristics were investigated as possible correlates of BZD dependence severity. Dependence severity was measured by the three subscales of the Benzodiazepine Self-Report Questionnaire, comprising problematic use, preoccupation and lack of compliance. Findings: In multivariate analyses, problematic use was associated with more GP contacts in the past 6 months (β=0.170, P=0.001) and severity of insomnia (β=0.145, P=0.004). Preoccupation was related to anxiety severity (β=0.194, P=0.001), antidepressant use (β=0.197, P<0.001), alcohol dependence (β=0.185, P<0.001) and a higher daily dosage of BZD (β=0.160, P=0.001). Lack of compliance was associated with higher age (β=0.122, P=0.03), unemployment (β=0.105, P=0.04), insomnia (β=0.129, P=0.01), antidepressant use (β=0.148, P=0.002) and alcohol dependence (β=0.108, P=0.02). Conclusions: Insomnia, antidepressant use and alcohol dependence may increase the risk of benzodiazepine dependence among individuals who use benzodiazepines. © 2012 The Authors, Addiction © 2012 Society for the Study of Addiction.