All persons acquitted by reason of insanity during this period were identified through records of the New York State Department of Mental Hygiene. Basic data resulting to each patient were then abstracted from these files and from the records of State correctional services and criminal justice departments. A comparison group of persons admitted to New York State prisons from 1971 through 1975 was drawn. Findings indicated that a total of 278 persons were adjudicated NGRI by New York courts. A total of 86 percent were male and 14 percent were female. Whites, females, and older persons were overrepresented in the NGRI group in terms of total adjudications. A total of 56 percent of the males and 74 percent of the female NGRI subjects had no prior psychiatric hospitalizations. Crimes against persons comprised the largest category of offenses for both men and women; homicide was the most frequent crime. Over four-fifths of the crimes involved a single victim who, in 64 percent of the cases, was known to the patient prior to the criminal act. For females, the predominant victims were their progeny; for males, well-known acquaintances were most often the victims. Upon admission for their NGRI hospitalizations, 68 percent of the patients were diagnosed as psychotic. Personality disorders were the second most frequent diagnostic category. The data suggest no particular relationship between type of crime and length of hospitalization, although those acquitted for murder had the longest average hospitalization: 488 days. Following discharge from their enforced NGRI commitment, 22 percent of the dischargees experienced subsequent hospitalization. A pronounced increase in successful NGRI pleas was observed during the study period. Within the sample were members of certain categories of individuals for whom society makes special allowances. These categories include mothers who commit infanticide, police officers, and previously respectable middle class individuals with whom the courts and juries can empathize. It is suggested that the statutory language applicable to NGRI pleas be revised to eliminate apparent inequities. One footnote, seven tables, and 14 references are provided in the study.