Anabolic androgenic steroid (AAS) abuse has become a public health problem in many countries, and is associated with many psychiatric disorders. Epidemiological studies have also found increasing numbers of sleep disorders reported by individuals using AASs. The purpose of this study was to evaluate sleep patterns and disorders in anabolic androgenic users who practice resistance exercise. The sample comprised 58 males divided into three groups: (1) 20 current AAS users aged 26 +/- 1.2, (2) 21 controls with no history of AAS use, aged 26 +/- 1 and (3) 17 sedentary men with no sleep disorders aged 27.2 +/- 0.34. The volunteers spent a night in the sleep laboratory for polysomnography. Comparing the three groups, the user group showed reduced sleep efficiency and more wakings after sleep onset than the sedentary group (P = 0.001). The sedentary group showed a higher percentage of stage 4 than the non-users group. We suggest that using of anabolic steroids reduced sleep efficiency and alters sleep architecture.