FEDERAL INMATE POPULATIONS ARE SOARING, WITH SPACE PROVISIONS LAGGING BEHIND, THUS MAKING CROWDING A SERIOUS PROBLEM IN PRISONS. THE LITERATURE ON RESEARCH INTO THE EFFECTS OF CROWDING ON HUMAN BEHAVIOR IS REVIEWED. THE RESULTS OF THE STUDIES CITED INDICATE THAT HIGH DENSITY AND CONFINEMENT ARE INEXTRICABLY LINKED TO ELEVATED AROUSAL LEVELS, WITH SYMPTOMOLOGY BEING A POSSIBLE BYPRODUCT OF THIS ASSOCIATION. IN AN ATTEMPT TO TEST THESE FINDINGS IN THE CONTEXT OF A PRISON SETTING, A STUDY WAS UNDERTAKEN TO TEST THE RELATIONSHIP BETWEEN MISCONDUCT RATES AND DENSITY LEVELS IN 4 TYPES OF FEDERAL PRISONS: JUVENILE-YOUTH, YOUNG ADULT, INTERMEDIATE-TERM ADULT, AND LONG-TERM ADULT. DATA WERE GATHERED FROM 37 INSTITUTIONS. FORMS WERE MAILED TO THE CHIEF CORRECTIONAL SUPERVISORS FOR DISTRIBUTION TO CUSTODIAL PERSONNEL, WHO COMPLETED THEM. THE FORMS ASKED FOR FREQUENCY OF MISCONDUCT INCIDENTS OCCURING FROM JULY 1973 TO JUNE 1976. RULE INFRACTIONS WERE SEPARATED INTO THE FOLLOWING OVERLAPPING CATEGORIES: (1) INFRACTIONS ADJUDICATED BY THE INSTITUTIONAL DISCIPLINARY COMMITTEE (TYPICALLY CONTRABAND, HOMOSEXUALITY, ESCAPES, AND ASSAULTS); (2) TOTAL ASSAULTS (INMATE/INMATE PLUS INMATE/STAFF); AND (3) INMATE/INMATE ASSAULTS. AN INDEX OF DENSITY WAS CALCULATED BY DIVIDING THE AVERAGE DAILY POPULATION FOR AN INSTITUTION BY THE YEAR-END PHYSICAL CAPACITY. OVERALL CORRELATIONS SHOWED THAT HIGH DENSITY IS ASSOCIATED WITH HIGH RATES OF ASSAULTIVENESS, WITH THE RELATIONSHIP BEING STRONGEST IN INSTITUTIONS HOUSING YOUNG ADULTS. WHILE COSTLY EXPANSIONS OF SPACE ARE DEEMED UNREALISTIC AT THE PRESENT TIME, IT IS PROPOSED THAT WITHIN EXISTING SPACE LIMITATIONS, ARCHITECTURAL AND PROGRAM MODIFICATIONS CAN BE MADE SO THAT INMATES' PERCEPTIONS OF CROWDING CAN BE REDUCED. RECOMMENDATIONS ARE BASED IN THE BELIEF THAT REDUCING THE EXTERNAL STIMULI TYPICALLY ASSOCIATED WITH CROWDING CAN HAVE THE SAME EFFECT AS REDUCING DENSITY. DATA OBTAINED FROM THE STUDY ARE INCLUDED, ALONG WITH REFERENCES. (RCB)