This study analyzes connections between online chatting and the Internet Addiction Disorder (IAD). In the research are compared two groups of respondents--Czech online chat users and Czech university students. The set of answers designed by Kimberly Young, of the University of Pittsburgh, was the common base for research. The research showed that IAD is known among university students, that some of them spend an enormous time on the Internet, and that many of them feel it is a problem. The research also clearly showed that the most serious chat users more often have problems with IAD than other university students.