Abstract: According to the definition of World Health Organization (WHO), life style is the method of life built on specific behavioral patterns. We performed a survey among a group of Iranian medical students to identify their health related life style. A cross sectional study was performed by using the questionnaire. In this process, three-hundred out of all 800 medical students who have entered the medical faculty of Tabriz Medical University, Iran during 1998 and 2004 participated in the survey. The questions were designed based on the health behaviors among the medical students. Approximately 14% of all respondents reported that they used tobacco. Fifty eight percent of smokers resided in the students� dormitory. Half of the smokers declared that they smoke less than 5 cigarettes a day while 16.7% smoked more than fifteen cigarettes per day. Thirteen percent of the students drink alcoholic beverages. Furthermore, 50% of the students declared the ages of 19-22 as the age of first alcohol intake. Approximately 59% said that they eat food regularly at all the three main meals. Also 45.5% of females and 54.5% of males eat junk foods more than 5 times a week. Nearly 67% of the women and 33% of men eat fruit and vegetables more than 4 servings a week. Exercise was more frequent in the lower year medical students. This study demonstrated that unhealthy behaviors are increasing among the medical students; however Iranian medical students� unhealthy habits are lesser than those of university students assessed in America and European countries.