VISUAL TERRITORIAL DISPLAYS IN THIS STUDY INCLUDED SIGNS (NO TRESPASSING, KEEP OUT, ETC), BARRIERS SUCH AS FENCES, PERSONALIZATIONS (WELCOME MATS, INITIALS ON CHIMNEYS), AND EXTERNAL SURVEILLANCE DEVICES. THE RESPONDENTS WERE 157 HOMEOWNERS AGED 65 AND OLDER FROM SEVERAL PREDOMINANTLY WHITE, MIDDLE CLASS COMMUNITIES IN PENNSYLVANIA. DATA WERE COLLECTED THROUGH UNOBTRUSIVE OBSERVATION OF TERRITORIAL MARKERS (MEASURE OF TERRITORIAL BEHAVIOR) AND RESPONSES TO A THREE-PART ORAL QUESTIONNAIRE. ATTITUDINAL MEASURES OF THEIR FEAR OF CRIME INDICATED THAT HIGH TERRITORIAL ELDERLY WERE LESS FEARFUL OF BEING VICTIMIZED THAN WERE LOW TERRITORIAL ELDERLY. STRONG SEX DIFFERENCES IN AMOUNT OF FEAR WERE ALSO FOUND, AS WERE INTERACTIONS OF TERRITORIALITY WITH THE SEX AND WITH THE LIVING ARRANGEMENT (ALONE OR NOT ALONE) OF THE HOMEOWNER. THE RESULTS ARE DISCUSSED IN THE CONTEXT OF MASTERY OF THE ENVIRONMENT BY THE ELDERLY. (AUTHOR ABSTRACT MODIFIED)...EB