The purpose of this study was to investigate the phenomenon of loneliness in delinquent adolescents with regard to types of delinquency offenses committed, demographic characteristics, and personality characteristics in the areas of interpersonal needs for inclusion, control, and affection. The types of delinquency offenses were categorized as burglary, runaway, drugs, assault, and incorrigible. The demographic variables examined were age, sex, race, family rank or birth order, family structure in terms of parental presence, family income level, religion, and geographic locale. A sample of 98 adolescents was obtained from juvenile detention facilities in three metropolitan areas in the United States. Subjects ranged in age from 12 to 18. Subjects were asked to complete the Loneliness Questionnaire as a self-reported measure of loneliness. Subjects also provided information about themselves relative to demographic characteristics and completed the FIRO-B Questionnaire, which measured interpersonal needs for inclusion, control, and affection. The results revealed no significant differences with regard to any of the demographic variables when the effect of each was considered alone. However, there was a significant effect on loneliness by income when considered jointly with other demographic variables. Adolescents from the middle income group expressed more loneliness than those from the upper and lower income groups. No significant differences were observed with regard to personality characteristics related to interpersonal needs for inclusion and affection, but delinquent adolescents with medium to high needs for control indicated significantly more feelings of loneliness than delinquent adolescents with low needs for control.