Background: Acne vulgaris is a common disease that affects the majority of the adolescent population and a large number of young adults with (90%) of all teenagers being affected by some degree. Androgens have been shown to play an important role in sebum production, and sebum over production, which in turn, is one of the primary pathogenic factors in acne formation. Obesity and overweight are often accompanied by peripheral hyperandrogenism. Body mass index (BMI) is frequently used to define these disorders clinically. Aim of study: To assess the frequency and severity of acne vulgaris among Tikrit Medical College students and its relation with Body Mass Index. Patients and Methods: A cross sectional study that done in Tikrit Medical College during the period extending from the first of February 2017 to the end of June 2017, 153 students are included, each of them was assessed by a prepared questionnaire, students are examined clinically of acne lesions, its severity and classified in to mild, moderate, severe and very severe according to the global acne grading system, BMI is measured for each student with acne vulgaris according to World Health Organization definition by checking weight and height. Results: All over frequency of acne vulgaris was (46%) among a group of Tikrit Medical College students, (62%) of them were females, (38%) of them were males, mild acne represent (52%), of study cases, (65%) of cases was within normal weight. There was extremely significant relation between BMI, family history and severity of acne (p value<0.0001). There was no statistically significant relation between gender and severity of acne vulgaris (p value 0.138), no significant relation between smoking and severity of acne (p value 0.5). Conclusions: After age of puberty, the frequency of acne vulgaris decreased significantly as the age increased. BMI and family history of acne could be risk factors for increase severity of acne vulgaris. No effect of smoking on severity of acne vulgaris.