Anabolic-androgenic steroids (AAS) cause psychiatric and cognitive abnormalities. We performed the first Diffusion Tensor Imaging study of long-term AAS users. Fractional anisotropy (FA) was higher in AAS users in an amygdala network tract. Among AAS users, FA in this tract was positively associated with lifetime AAS dose. The FA abnormality is consistent with prior human and animal studies of AAS effects.