THE STUDY WAS CONDUCTED AT THE FEDERAL CORRECTIONAL INSTITUTION (FCI) AT TALLAHASSEE, FLORIDA, A MEDIUM SECURITY INSTITUTION, FROM NOVEMBER 1971 THROUGH OCTOBER 1974. DURING THIS PERIOD, FCI WAS RENOVATING ITS DORMITORIES AND WAS RELOCATING THE EXTRA INMATES IN WITH OTHER PRISONERS. THREE INDEPENDENT VARIABLES - INMATE POPULATION, TOTAL SPACE, AND SPACE PER RESIDENT - WERE CORRELATED WITH THE TOTAL NUMBER OF DISCIPLINARY VIOLATIONS AND THE RATE OF VIOLATIONS PER 100 RESIDENTS. PARTIAL CORRELATIONS WERE ALSO COMPUTED BETWEEN POPULATION AND SPACE AND THE NUMBER AND RATE OF INCIDENT REPORTS. THE RESULTS OF THE STUDY INDICATED THAT, IN A PRISON SETTING, WHERE CROWDED CONDITIONS ARE CHRONIC RATHER THAN TEMPORARY (AS IN LABORATORY RESEARCH) AND WHERE PEOPLE PRONE TO ANTISOCIAL BEHAVIOR ARE GATHERED TOGETHER, THERE IS A CLEAR ASSOCIATION BETWEEN RESTRICTIONS ON PERSONAL SPACE AND THE OCCURRENCE OF DISRUPTIVE AND AGGRESSIVE BEHAVIOR. HOWEVER, SINCE THE CHANGES IN AVAILABLE SPACE CORRELATED MORE STRONGLY WITH DISRUPTIVE BEHAVIOR THAN DID CHANGES IN THE NUMBER OF RESIDENTS, SUPPORT IS SUGGESTED FOR THE THEORY THAT THERE ARE DIFFERENT EFFECTS ASSOCIATED WITH REDUCING AVAILABLE SPACE AND INCREASING THE NUMBER OF INDIVIDUALS IN A GIVEN SPACE.