The medical charts of 253 patients admitted to an acute psychiatric inpatient unit were reviewed for evidence of threats of violence within the two weeks before admission and violent behavior during the first three days of hospitalization. Fifty-eight percent of the patients who had made threats before admission required seclusion for dangerous behavior in the hospital, and 32 percent of the patients who had made threats physically assaulted someone in the hospital. The association between preadmission threats and subsequent violence was especially strongamong schizophrenic patients. Compared with schizophrenic patients who did not threaten others, those who bad made preadmission threats were more likely to be physically and verbally assaultive and were more likely to require seclusion. Manic patients who had made threats were more likely than those who had not made threats to be verbally assaultive while in the hospital.