The mobile phone usage is one of the modern phenomena of the electronic century that has increased between the families especially among the youth in Iran since a decade ago. The number of mobile users in the word increased from 12.4 million in 1990 to 5.3 billion in 2010. The most recent estimates indicate that the number of mobile users in Iran is now amounted to 41 million, i.e., 54 percent of the total population. It is also estimated that more than 85% of Iranian will be mobile owner until 2012. To us, the mobile has positive, negative, social and moral effects, but all the families don’t attend to negative aspects of this technology. The aim of this study is, therefore, to determine the pattern of mobile phone usage among students of Yazd Shahid Sadoghi University of Medical Sciences, as our sample case. This is the results of a cross sectional study and the samples were selected by simple random sampling from 245 students that were living in the university dorms. The data was collected and validated by using a questionnaire that it’s reliability and validity was determined by calculating the Cronbach alpha (α=0.835) and test- retest method. The questionnaire had two sections; 1- the demographic section; and, 2- a section that included questions that should have determined the pattern of mobile usage. The data were analyzed with SPSS, using Chi-squre test, ANOVA and Pearson correlation tests. Some findings indicate that 53% of female and 39% of male students decided to have a mobile set after they were accepted to attend the university. Also, there was a significant consequential difference between male and female student sin terms of a change in their life style. For instance, some 14% of female and 24% of male students argued that they were experiencing sleep disturbance after they were using mobile phones. The results also indicate that there is a significant decrease in student rate of communication with their family as opposed to an increase in communication with friends after using the mobile (5% and 8%) respectively. It is also worth mentioning that there is a need to educate the students how to be aware of the advantages and disadvantages of mobile usage.