This chapter reviews the neurochemical imaging literature in the anxiety disorders, focusing on key findings in post-traumatic stress disorder (PTSD), panic disorder (PD), social anxiety disorder (SAD) and generalized anxiety disorder (GAD). It provides a partial review of preclinical and human investigations of several neurochemical systems relevant to neurochemical imaging of anxiety disorders: namely the 5-HT, gamma-aminobutyric acid-benzodiazepine (GABA-BZD) and dopamine (DA) systems. Genetic analyses of polymorphisms of the major DA metabolizing enzyme catechol-O-methyltransferase (COMT) have suggested an association between specific polymorphisms and anxiety disorders, although these findings await replication. Several studies have utilized 1H-magnetic resonance spectroscopy (MRS) to investigate potential abnormalities in N-acetyl-aspartate (NAA), choline (CHO), creatine (CR) or lactate in GAD. As anxiety disorders are frequently comorbid with mood disorders, investigations of patients with anxious depression may be informative in determining specificity of neurochemical abnormalities.