In a cross-sectional investigation of the properties of DSM-III-R panic disorder (PD), panic disorder with agoraphobia (PDA), and agoraphobia without history of panic disorder (AWOPD), we analyzed demographic, descriptive, comorbidity, treatment, and course data for 562 subjects with PD, PDA, or AWOPD in a multicenter anxiety-disorders study. In general, AWOPD subjects had the worst functioning and PD subjects the best, as measured by length of intake episodes, education attained, likelihood of receiving financial assistance, depressive comorbidity, and likelihood of having experienced 8 weeks symptom-free. Panic disorder with agoraphobia was the most common disorder and emerged as a condition intermediate in severity between the other two. Treatments received varied little by diagnosis. Most subjects received medication, usually benzodiazepines. Psychodynamic psychotherapy was the most frequently received psychosocial treatment; cognitive and behavioral approaches were less common. Subjects classified with AWOPD were the most likely to have received exposure therapies.