OBJECTIVE. Data on persons known to have committed homicide during a 13- year period were studied to determine factors associated with increased risk of repeating homicide. METHODS. Between 1981 and 1993, a total of 1,649 homicides were committed in Finland. In 1,089 cases (66 percent), the offenders received an exhaustive forensic psychiatric examination. Data from reports of these examinations were analyzed to determine whether mental disorder and other factors were associated with homicide recidivism. RESULTS. Thirty-six homicide recidivists were identified. Twenty-four were alcoholics, 23 had a personality disorder, in most cases combined with alcoholism, four had schizophrenia, and two had major depression. Homicidal behavior was ten times more likely in men who had committed a previous homicide than in the general male population. Alcoholism increased the odds ratio of additional homicidal behavior in male homicide offenders about 13 times, and schizophrenia increased the odds ratio more than 25 times. During their first year after release from prison, male homicide offenders were about 250 times more likely to commit homicide than members of the general male population. CONCLUSIONS. The data suggest that mentally abnormal offenders are overrepresented among homicide recidivists in Finland. The risk of repeat homicide appears to be very high during the first year after release from prison.