Purpose: Purpose: The aim of this study was to identify the condition to use social networking service and mental health among nursing college students. Methods: In this study, 277 college students were selected by a convenience sampling method. Data were collected through personal interviews in the form of questionnaires from May 23 to 31, 2011 and analyzed using SPSS/PC Win 12.0 program. Results: The mean scores of SNS addiction and mental health were $1.34{pm}0.30$and $2.25{pm}0.39$. The SNS addiction of the nursing college students was significantly different according to the time of SNS and the reason of internet use. The mental health of the nursing college students significantly differed according to the method of SNS. The SNS addiction and mental health showed the significant negative relationship. The factors influencing mental health were SNS addiction score and method of SNS use. Conclusion: Therefore, it is necessary to offer controlling method of SNS use time a day for nursing college students through regular curriculum.