A GROUP OF 137 NATIVE WHITE SUBJECTS WAS GIVEN THE U.S. PUBLIC HEALTH SERVICE CLASSIFICATION TEST, AND A MEAN LETTER INDICATING AVERAGE INTELLIGENCE WAS ATTAINED. TWO SURVEYS WERE MADE WITH PERSONNEL FORM R-2, A GROUP PERSONALITY SCREENING INVENTORY, WITH 174 SUBJECTS, INDICATING SEVERE TROUBLEMAKING AND HIGH NEUROTIC TENDENCIES. DETAILED INDIVIDUAL TESTS WERE CONDUCTED WITH 51 SUBJECTS SELECTED BY THE MEDICAL CENTER STAFF AS BEING TYPICAL EXAMPLES OF NONPSYCHOTIC, NONFEEBLEMINDED CRIMINAL PSYCHOPATHS. THE RESULTS OF THE WECHSLER BELLEVUE INTELLIGENCE TESTS AND THE RORSCHACH METHOD OF PERSONALITY DIAGNOSIS WITH THESE SUBJECTS ARE REPORTED. A MARKED DISCREPANCY WAS FOUND BETWEEN INTELLIGENCE AS INDICATED BY I.Q. (INTELLIGENCE QUOTIENT) SCORES AND THE ACTUAL LEVEL OF INTELLECTUAL EFFICIENCY OBSERVED IN THE RORSCHACH TEST. RORSCHACH FINDINGS INDICATED THAT THE CRIMINAL PSYCHOPATH POSSESSES AN UNDEVELOPED, MALINTEGRATED, MALFUNCTIONING PERSONALITY STRUCTURE SIMILAR IN MANY RESPECTS TO THAT FOUND IN PSYCHONEUROSES. THE RORSCHACH METHOD OF PERSONALITY DIAGNOSIS WAS FOUND TO BE AN EFFECTIVE INSTRUMENT FOR REVEALING THE BASIC ORGANIZATION OF CLINICALLY DIAGNOSED CRIMINAL PSYCHOPATHS. (RCB)