This longitudinal study investigated the extent to which the use of mobile phone text messages, including e-mail and short message service, affected freshmen's loneliness during the transition to college. A total of 83 freshmen completed measures of loneliness and social network at the beginning and end of their first semester. Perceived utility of mobile phone text messages was assessed at the beginning of the semester. Results showed that perceived functional usefulness and affiliation fulfillment of text messages affected formation of social network during the period. It was found that the higher the functional usefulness, the larger increase in the number of messages to college friends, and the higher the affiliation fulfillment, the less important the text messages to pre-college friends. Furthermore, it was noted that the more important the relationship with pre-college and college friends that was not dependent on text messages, and the fewer messages to pre-college friends, the less the loneliness. In contrast, greater importance of text messages to pre-college friends was associated with an increase in loneliness.