Purpose: This study aims to determine the knowledge and behaviour changes, Premenstrual Syndrome (PMS) frequency and the factors affected by this frequency in order to find out the effect of knowledge level in the PMS, in professional high school for health care, a high school for females and Florence Nightingale Vocational School of Nursing students. Materials and methods: Student were questioned with answering- under- observation technique in May 2000. The height and weight measurements of each student have been taken. Result: Out of 357 participants, 51.8% were health and 48.2% were classical high school students. Average menarche age is 13.7±1.61 years. 84.3% of students were aware of the subject prior to the menstruation. The most frequent complaints of menstruation were abdominal and groin severe pain and cramp (45.9%), abdominal tightness and swelling (45.6%), and tiredness and indolence (43.9%). In the study, the PMS frequency was found to be 42.7%. There was no any significant difference between PMS and the type of the school. However, the relationship between PMS and irregular attendance in the school was found out to be statistically significant (p: 000088 ). The BMI ( Body Mass Index) average in our study was 20.57±2.47. According to BMI, 6.5% of students were found to be chronically insufficient of energy, 3.9% with excess weight and 0.2% fat. There was no any significant relationship determined between chronic energy deficiency and PMS. Conclusion: To our point of view, an inevitable part of health education to be given to all sections of the society must be the sexual education.