Background:Lack of knowledge regarding polycystic ovarian syndrome and poor lifestyle choices are considered to be the major factor leading to polycystic ovarian syndrome. Aim of study: Was to assess knowledge and attitude of late adolescent girls regarding polycystic ovarian syndrome. Design: Descriptive research design was utilized. Setting: This study was conducted at Technical Institute of Nursing at Benha University. Sampling: A purposive sample of 239late adolescent girls met the inclusion criteria. Tools of data collection: Two tools were used. I) A structured interviewing questionnaire which consisted of three parts: demographic characteristics, menstrual history of girls and knowledge of late adolescent girls regarding polycystic ovarian syndrome. II) Late adolescent girls` attitude towards polycystic ovarian syndrome. Results: More than half of late adolescent girls had unsatisfactory knowledge about polycystic ovarian syndrome. More than half of late adolescent girls had negative attitude toward polycystic ovarian syndrome. There was positive correlation between total knowledge and total attitude scores regarding polycystic ovarian syndrome (p-value 0.001). Conclusion: There was unsatisfactory knowledge and negative attitude regarding polycystic ovarian syndrome among late adolescent girls. Recommendation: Implementing an educational program about risk factors and preventive measures of polycystic ovarian syndrome among adolescent girls.