This article reviews the evidence from randomized, placebo-controlled trials and meta-analyses of pharmacological treatments of the following anxiety disorders: generalized anxiety disorder, panic disorder, social anxiety disorder, and post-traumatic stress disorder. There is evidence from multiple randomized, placebo-controlled trials to support the use of selective serotonin reuptake inhibitors as first-line pharmacotherapy in these disorders, and a number of the selective serotonin reuptake inhibitors have received US Food and Drug Administration approval for these indications. Serotonin-norepinephrine reuptake inhibitors are now emerging as first-line treatments for these anxiety disorders alongside the selective serotonin reuptake inhibitors and have been US Food and Drug Administration-approved for some of these indications as well. Benzodiazepines are also effective treatments for anxiety disorders, and although this medication class has the advantage of a rapid onset of action, their use is limited by their potential for abuse and lack of antidepressant properties. In addition to reviewing the clinical trials that have investigated the anxiolytic effects of these commonly used medications, we review the evidence for novel uses of other agents, including anticonvulsants and atypical antipsychotics, in anxiety disorders.