This study was carried out to determine the general characteristics of Internet use among university students in Turkey and to examine the relation between the Internet use and the psychosocial conditions of the students. Among the 730 university students who participated, the average age was 20.84 (SD = 1.95), and the majority were females. The average Internet use period of the students was detected as 2.80 (SD = 1.33) years for females and 3.59 (SD = 1.60) years for males. The average score of the Online Cognition Scale (OCS) used for determining problematic use was 84.64 (SD = 33.50): for females, 77.99 (SD = 30.70); for males, 92.16 (SD = 34.96). Students of social sciences scored highest on the OCS. It was determined that as the OSC score increased, students' performance of Internet activities such as general information searches and academic research decreased and that performance of interactive and entertainment Internet activities such as chat, financial transactions, game playing, sex, down-loading programs, and listening to MP3s increased. While a positive correlation was found between problematic use and loneliness and depression, a negative correlation was found between problematic use and perceived social support.