Background: Eating disorders are type of psychiatry disorder. When Persons are havingabnormal features ofeating habits that badly affects physical or mental health. Anorexia Nervosa is a eating disorder that is characterized by restrictions of eating which leads to abnormal weight loss and having fear of obesity or increasing body weight. It isakind of selfstarvation due to presence of eating disorder which leads to restriction in eating and other abnormal behaviors that prevents a person to gain his/her weight. In comparison to male, females are more affected with this disorder. Higher number of girls is affected with common psychological problems like anxiety, sleeping disorder, depression, tension, and eating disorders. Studies have shown that most common psychological disorders among adolescent is anorexia nervosa. Objectives: To evaluate the level ofknowledge regarding anorexia nervosa, to determine the association between the knowledge ofanorexia nervosa among the adolescent girls with selected demographic variables. Methods: A descriptive survey design and purposive sampling technique was used for selecting the sample. Total 370numbers of samples(Adolescent girls 16-19yrs) were taken from different selected colleges, Bhubaneswar. Collected data were analyzed by using descriptive and inferential statistics. Results: Study revealed that Majority adolescentgirls were having intermediate knowledge about anorexia nervosa and there were significant association found between demographic variables(age, family income, family pattern, dietary pattern, education of both parents) with the knowledge in anorexia nervosa among adolescent girls. Conclusion: Study concluded that adolescent girls had inadequate knowledge about anorexia nervosa. So, due to lack of knowledge about consequences of improper intake of diet for over beauty consciousness that may leads to development of physical and psychological problems in future.