Research has indicated significant comorbid psychopathology with chronic posttraumatic stress disorder (PTSD) in samples of war veterans. The present paper examines the issue of comorbidity in a disaster sample to learn whether findings from veterans generalized to this event. A total of 193 subjects exposed to the Buffalo Creek dam collapse of 1972 were examined 14 years later using diagnoses derived from the Structured Clinical Interview for DSM-III (SCID). Past and present PTSD was found in a significant portion of the sample. Major depression was the next most common diagnosis and was highly related to PTSD. Anxiety disorders were also common. The overlap with other diagnoses was quite similar to that found in a sample of Vietnam veterans we studied earlier, except that the disaster sample had fewer dysthymic disorders, substance abusers, and antisocial personality disorders. Possible explanations for comorbidity in chronic PTSD were discussed and it was suggested that the morphology of PTSD may be quite stable in at least some other nonveteran trauma populations.