Psychological tests can provide important information about the motivations of offenders and their relationships with the environment. Test methods, however, have certain limitations. Most psychological tests are based on clinical psychology concepts not primarily designed to address specific legal questions. Further, diagnoses concentrate rather simplistically on habitual personality traits and neglect the fact that the offender's motivation and decision to commit a criminal act are often determined by actual circumstances accompanying the act at the time and by temporary psychological factors related to the criminal act. In addition, traditional testing procedures fail to achieve the unity between regnosis, diagnosis, and prognosis that a reliable forensic appraisal requires. Standardized psychometric intelligence and personal tests used at the Berlin Charite University-Hospital to assess both young and adult offenders are described, and test findings related to intelligence and personality diagnostics are presented. The author concludes that psychological tests must be employed in conjunction with case records, personality and offense evaluations, and other neuropsychiatric tools at the forensic expert's disposal for their full value to be realized. 18 references, 1 table, and 5 figures