Atypical depression is the most common form of depression in outpatients, but compared with melancholia, little is known about its comorbidity, course, and treatment. Beyond the well-characterized constellation of symptoms that define atypical depression (mood reactivity, hypersomnia, leaden paralysis, hyperphagia, and rejection sensitivity), specific Axis I and II comorbid conditions may differentiate atypical from other depressed patients. Similarly, age at onset, duration of episodes, frequency of relapses and recurrences, and frequency of complete remission in atypical depression may be different. It has not even been established if atypical depression is a stable subtype or if it is just one of several forms of depression that an individual may express during a lifetime of recurrent depressions. Monoamine oxidase inhibitors (MAOIs) are superior to tricyclic antidepressants (TCAs) for the treatment of atypical depression, but few studies have compared MAOIs to the newer generation of antidepressants (SSRIs, bupropion, venlafaxine, nefazodone, and mirtazapine). Because of the favorable benefit/risk ratio, clinicians tend to use these newer antidepressants for all outpatients, including those with atypical depression, even though the literature is limited. A review and critique of the relevant literature on atypical depression will be presented.