At the end of 2002, about 91% of mobile telecommunications service subscribers have mobile phones with the mobile internet access function. However, despite the rapid spread of mobile internet phones, the number of real mobile internet users is very small. In this situation, this paper focuses on the effect of consumer demographics such as sex, age, job, etc. and consumer life-style on the use of mobile internet. This study tries to find the answers about the following questions ; 1) Which consumer demographic variables affect the use of mobile internetulcorner 2) How can we categorize the consumers with the mobile internet phonesulcorner 3) What are the characteristics of categorized groups and is there any difference in using the mobile internetulcorner For this purpose, an off-line survey was conducted over 1,500 consumers with the mobile internet phones. This study concludes as follows ; The important demographic factors of the use of mobile internet are age, job, marriage, academic career and personal spending money. Totally viewed in the consumer demographics, the typical type of mobile internet users can be described as the young student. On the other hand, sex and family income variables do not significantly affect the use of mobile internet. And the mobile internet users can be categorized by the life-style into four distinct groups, which are named as the innovation oriented group, the practicality oriented group, the conservation oriented group, the ostentation oriented group. These findings show that the consumer life-style have various effects on the use of mobile internet.