Previous studies have demonstrated relationships between poor premorbid adjustment and a variety of phenomenological and neurobiological indices in schizophrenic patients. Using the Modified Premorbid Adjustment Scale we re-examined these relationships in a large sample (n = 131) of schizophrenic patients. Subjects were evaluated with the Comprehensive Assessment of Symptoms and History (CASH) and magnetic resonance imaging. Multiple correlation indicated that poor premorbid adjustment was significantly associated with prominence of negative symptoms, early age of onset, educational problems, chronicity, and neurological soft signs, but not with any MRI measures. These results confirm poor premorbid adjustment as an important predictor of a malignant form of schizophrenia as evidenced by an earlier age of onset, poorer educational performance, prominent negative symptoms, presence of soft signs, and chronicity of course.