Abstract: Background: Polycystic ovarian disease is a condition in which adolescents girls has an imbalance of females sex  hormones. This might lead to change in the menstrual cycle, cyst in ovary, failure to conceive and other health problems. It is a common health problem among adolescents girls. Objectives: 1. To assess the knowledge regarding polycystic ovarian disease among adolescents girls. 2. To find the association between the knowledge regarding polycystic ovarian disease with their selected demographic variables among adolescents girls. Material and Methods: Quantitative approach and non-experimental descriptive research design. The study  conducted in Vinayaka Mission’s college of Nursing, Karaikal. 6 samples of adolescents girls were selected by Non-probalibity convenient sampling technique. The tool consists of two sections. Section-A consists of demographic variables and Section-B consists of Structured knowledge questionnaire regarding Polycystic ovarian disease .Result: The study result shows that majority 60% (36) of the adolescents girls had inadequate knowledge, 33% (20) of the adolescents girls had moderate knowledge, and 6.6% (4) of the adolescents girls had adequate knowledge regarding polycystic ovarian disease. There is a significant association between the knowledge regarding polycystic ovarian disease among adolescents girls with their demographic variables such as dietary and source of information regarding polycystic ovarian disease. There is no association with respected to other variables.