This study aims to investigate a seriousness of gambling problems by gambler sub-type among college students in Korea. Data were collected from 581 college students of Seoul, Gyeonggi-do, Chungcheong-do, and Gyeongsang-do area through the questionnaire and a total of 577 questionnaires were statistically processed excluding the questionnaires of missing answers. To analyze the gambling problems by gambler sub-types among college students, a cross-sectional research design was used in the study. Data were analyzed using Statistical Package for the Social Sciences. Among the 577 respondents of this study, 62.2% had gambling experience and especially 6.1% had illegal gambling experience. The prevalence rate of gambling addiction by the Canadian problem gambling index was 14.0% in this study. A significant statistical difference between gambler sub-types in gender, college grade, spending money, beginning of the first gambling, illegal gambling experience, route to start gambling, self-esteem, impulsivity, and irrational gambling belief was found in this study. The number of respondents who knew free counselling centers when there was a gambling problem was only 20 (3.5%), so it is quite required to carry out preventive education and to publicize free counselling centers for a gambling problem. In case that the respondents have a gambling problem, what they wanted to be supported most was psychotherapy and counseling, family counseling, hospital treatment, group therapy or Gamblers Anonymous meeting, and financial and legal consultation. It is required to continue further surveys on gambling among college students and to take a proper measure preventing a gambling problem.