The institutions that have contributed to the Argentinean criminological tradition include the Psychiatric and Criminological Clinic of the Buenos Aires City Police, the Office for Medicolegal Studies of the former Federal Capital Reformatory for Male Juveniles, and the internationally known Criminology Institute. Criminological diagnosis in relation to police work includes psychiatric forensic observation to define and explain a perpetrator and why and how a crime was committed. The forensic medical staff -- comprising forensic physicians, psychiatrists, neurologists, toxicologists, hygienists, electroencephalographists, and psychologist who administer the personality and delinquent motivation tests -- meet the requirements of the Penal Code in providing information necessary for judges to determine sentences. Criminological diagnosis is also used to implement the requirements of the Penal Law in providing progressive treatment and the background information essential for the parole decision. The interaction of body types and physical problems with psychological findings is determined in the somatopsychic examination conducted for all offenders, and criminological diagnosis of juvenile offenders has revealed an increase in severe juvenile maladjustment among those belonging to the lower socioeconomic subculture. Criminological diagnosis has also been used to determine the extent and pattern of drug abuse among offenders. The concluding section provides an overview of some of the criminogenic aspects of Argentine society. Tabular data cover the characteristics of the 1971 convicted population of Buenos Aires and summaries of 5,000 criminological histories. Sections of the Penal Code relevant to criminological diagnosis are also provided.