The Internet has become an important part of many people’s lives across the world since its first launching in 1960s. In spite of its many beneficial roles for various new applications and services, the emergence of the Internet also has created a new problem called "problematic Internet use" or "Internet addiction," in which individuals experience interpersonal, school, or work-related problems due to excessive use of the Internet. However, since problematic Internet use is a relatively new phenomenon, research in this field has produced as yet a limited number of research studies. This study reviews available research related to defining, assessing, and measuring the problematic Internet use of college students, and examines characteristics related to Internet use for this population. This study utilizes a web-based survey with a randomly selected sample of registered undergraduate and graduate students of the University of Texas at Austin in 2006. The Internet Addiction Test (IAT) (Young, 1998) and the Online Cognition Scale (OCS) (Davis, 2002) were employed to measure aspects of problematic Internet use. Result scores of the Internet Addiction Test (IAT) showed that only 0.8 percent of the respondents were diagnosed as Internet users with significant problems, whereas 28.0 percent were classified with frequent problems. Consolidation of the percentage of respondents with the frequent problems and the significant problems resulted in a total of 28.8 percent presenting with problematic Internet use. A gender difference with regard to problematic Internet use was evident, with male students scoring higher on both the Internet Addiction Test and the Online Cognition Scale. Time spent online for non-academic purpose was positively correlated with problematic Internet use, whereas both age and GPA were negatively correlated with problematic Internet use. The hard science students were more likely to be problematic Internet users than soft science and fine arts students while freshmen students were more vulnerable to problematic Internet use than graduate students. Overall, the findings of this study support previous research except for Internet applications and services used by college students. The percentage of online chatting users has dramatically jumped from mere 9.1% (Scherer, 1997) to 56.4%. In contrast to this jump, the percentage of Usenet service use has decreased from 36.9% (Scherer, 1997) to 11.7%. Relatively new services such as blog/social networking and file sharing, which were not reported in earlier studies conducted by Scherer (1997) and Young (1996, 1998), have become increasingly popular. It seems that, as network technology is evolving and more services have become available, the trend of Internet use is also changing. / text