Background & aim: Breast cancer is the most common cancer among women in developed anddeveloping countries. Its early and rapid detect by screening methods can increase women’s survivalrate. Among breast cancer screening techniques, breast self-examination is the simplest, the mostapplicable and the least expensive screening method. The purpose of this study was to examine femalestudents’ knowledge, worry and screening behavior toward breast cancer in Urmia University ofMedical Sciences, 2014.Materials & methods: This cross–sectional study was conducted on 334 eligible and female studentsof Urmia University of Medical Sciences, in 2014. To collect data, a valid and reliable questionnairewas utilized. The questionnaire included demographic information, the students’ knowledge and theworry toward breast cancer. The study data were analyzed using descriptive statistics (frequency, meanand standard deviation) and inferential statistics (independent t-test, ANOVA and chi-square test).Results: The findings suggested that more than half of the cases (60.2%) were Turk concerning theirethnic, and about 65.3 of the subjects were studying in undergraduate level, and about 10% of studentswere reported to have a family history of cancer. Average score students' awareness about breast cancerwas a little more than average total score (23.13 ±4.77). But the average score of concerns about breastcancer was less than the average total score (6.77±2.56). Only 24.6% of the study samples have donethe breast self-examination behavior. Awareness and breast self-examination behavior had a significantrelationship with variables such as Grade Point Average, level of education and their academic year (P<0.05). A significant relationship was also observed between BSE and knowledge of students (P<0.05).Discussion: This study shows that health knowledge, health worry and breast self-examination behaviorwas inadequate, and the students were far from optimal situation. Therefore, it is essential that healtheducators and providers of health services design and implement educational programs and campaignsfor different groups of women, to improve their KAP (knowledge, attitude and practice) regarding breastcancer