Abstract: Self prescribing practices has become a substantial area in health sector due to mal-practices. This study was undertaken to determine the knowledge and perceptions of undergraduate students at University of Peradeniya about the Paracetamol usage by self medication practices. A pre validated questionnaire was administered to 273 randomly selected students in all five courses of Faculty of Allied Health Sciences, University of Peradeniya. Descriptive statistics and multiple logistic regressions were used in data analysis. Associations were evaluated using chi square tests. From all the respondents, 67.4 % were female and 32.6 % were male students. And most of the students were in the age range of 22 – 24years. Most of the respondents were not engaged in exercises or sports. Although self prescription pattern was followed by highest proportion of the study population, the disadvantages of this practice were emphasized by 65 % of students. Main practical reason reported for self prescribing of Paracetamol is having a good knowledge to use it properly and potential source of acquiring Paracetamol was pharmacies and retail shops. “Paracetamol should be taken with a doctor’s prescription” was reported to be the main overall concept of majority of students enrolled in all five courses and majority of students reported that self practicing of Paracetamol was harmful. The study determined that self prescription pattern in the use of Paracetamol is more common than doctor’s prescription practice among Allied Health Sciences students.