BACKGROUND:Data are presented on the general population prevalences, correlates, comorbidities, and impairments associated with DSM-III-R phobias. METHODS:Analysis is based on the National Comorbidity Survey. Phobias were assessed with a revised version of the Composite International Diagnostic Interview. RESULTS:Lifetime (and 30-day) prevalence estimates are 6.7% (and 2.3%) for agoraphobia, 11.3% (and 5.5%) for simple phobia, and 13.3% (and 4.5%) for social phobia. Increasing lifetime prevalences are found in recent cohorts. Earlier median ages at illness onset are found for simple (15 years of age) and social (16 years of age) phobias than for agoraphobia (29 years of age). Phobias are highly comorbid. Most comorbid simple and social phobias are temporally primary, while most comorbid agoraphobia is temporally secondary. Comorbid phobias are generally more severe than pure phobias. Despite evidence of role impairment in phobia, only a minority of individuals with phobia ever seek professional treatment. CONCLUSIONS:Phobias are common, increasingly prevalent, often associated with serious role impairment, and usually go untreated. Focused research is needed to investigate barriers to help seeking.