The purpose of this study was to identify the relationships among smart phone use motivations, addiction, and self-control in nursing students. Data were collected from June 10-18, 2013. Smart phone use motivations and addiction showed significant differences according to sex, record. Smart phone high-risk users got high-score in use motivations especially entertainment/leisure, service, and functionality, and low-score in self-control. The factors affecting smart phone addiction were record, tolerance, abstinence, difficulty of daily living, and aim for virtual world which accounted for 88.2%. Also factors affecting addiction were entertainment/leisure, flaunt/trend which accounted for 12.9%. In conclusion, smart phone use motivations was correlated positively with addiction, while addiction was correlated negatively with self-control. Therefore more positive and desirable ways of smart phone use, and plans for improvement of self-control should be studied.