Forty-three male and 53 female college seniors maintained the Rochester Interaction Record for 2 weeks, providing information about every social interaction of 10 minutes or more. Subjects then completed the revised UCLA (University of California, Los Angeles) Loneliness Scale and the Personal Attributes Questionnaire, measuring sex-role orientation. For both sexes, loneliness was negatively related to the amount of time spent with females and to the meaningfulness of interaction with males and females. However, meaningfulness with males was more important than meaningfulness with females. Femininity was negatively related to loneliness for both sexes and partially mediated the above relationships. There were sex differences, however, in the extent to which variables overlapped in predicting loneliness. For example, a large group of nonlonely males was characterized both by having meaningful relationships with males and by spending time with females, whereas a second group of nonlonely males was characterized simply by having meaningful relationships with males. The largest group of nonlonely females was characterized simply by having meaningful relationships with males, but another sizable group was characterized simply by spending time with females. Females doing both accounted for very little of the variance.