Anxiety disorders are common and disabling conditions. Current drug treatment methods have limitations including resistance, delayed efficacy and side effects. The advent of sophisticated imaging techniques and the production of highly selective receptor ligands have increased our knowledge of the biological mechanisms underpinning anxiety. Our aim is to review recent discoveries in important neurological systems to provide an understanding of important current anxiolytic targets. Some of these systems, such as GABA, have been implicated in anxiety disorders for decades, but a recent greater understanding is enabling more sophisticated targeting of treatments. In other systems, including the neuropeptides, we have now developed the pharmacological tools in human subjects to begin exploring their relationship to anxiety disorders. We review GABA, serotonin, glutamate, noradrenaline, dopamine and some neuropeptides herein.