Purpose: The purpose of this study was to investigate the influences of depression, stress, and self-efficacy on the addiction to cell phone use among university students. Methods: Data were collected through questionnaires from 563 students and analyzed by applying descriptive statistics, t-test, x2 test, and stepwise multiple regression with SPSS/WIN 16.0. Results: The proportion of depressed subjects was 52.6%. The addictive group scored higher than the non-addictive group in depression rate and stress, but scored lower in self-efficacy. Out of the subjects, 32.9% were found to be addictive users, 31.3% at potential risk, and 1.6% at high risk. Significant variables influencing addictive users were stress, self-efficacy, and the user's general characteristics including monthly spending money, sex, the hours of daily use, and the main method of use. Conclusion: It is concluded that such variables should be carefully considered in interventions for university students addicted to cell phone use.