The reliability, validity, and dimensionality of the revised UCLA Loneliness Scale (ULS) were studied with a group of 199 California college students. Other personality tests were administered to measure social anxiety, alienation, health locus of control, drinking-related locus of control, life satisfaction, and personal values. Sociodemographic measures included grade in college, sex, and age. Health-related behaviors assessed included meal regularity, exercise, hours of sleep, drug use, smoking, and alcohol use and negative consequences. The reliability was .90 for the 20-item ULS and .63 for the 4-item short form. Factor analysis indicated five dimensions which are lower-order dimensions of a higher-order factor of loneliness: most importantly, social isolation; followed by unavailability of empathic confidants, unavailability of support persons, lack of social integration, and lack of meaningful social relationships. Loneliness was significantly correlated with alienation; social anxiety; satisfaction with friends, sex life, family or home life, and self; and drinking-related locus of control. Health-related behavior was not significantly correlated. In this sample, males were significantly more lonely than females. Multiple regression anaylsis indicated that the personality variables accounted for sixty percent of the ULS variance. The ULS and the short form are included. (GDC)