The aim of the study was to assess the knowledge and prevention of upper respiratory tract infection among mothers of under five children at MCH center in tirupati. Objectives: • To assess the existing knowledge on prevention of hygienic health practices of under-five mothers on upper respiratory tractinfections. • To evaluate the effectiveness of structured teaching programme on upper respiratory tractinfections. • To associate the knowledge of under-five mothers regarding upper respiratory tract infection with selected demographic variables. Methodology: By using convenient sampling technique A quasi experimental single group pre-test and post-test design has been adopted. Fifty mothers of under five children were selected. and data collection was done by using a standardized and self-structured questionnaire. Results: Out of 50 mothers in pre-test 88(44%) had inadequate knowledge, 6(12%) had moderate knowledge and 0(0.0%) had adequate knowledge. In post-test 0(0.0%) had inadequate knowledge, 16(32%) had moderate knowledge and 68(34%) had adequate knowledge. Out of 50 mothers pre-test 10(20%) had inadequate knowledge on prevention, 38 (72%) had moderate knowledge on prevention and 2 (4%) had adequate knowledge on prevention. In post-test 0(0%) had inadequate knowledge on prevention, 13 (26%) had moderate knowledge on prevention, 37 (74%) had adequate knowledge on prevention. Out of 50 mothers total pre-test knowledge 19(38%), had inadequate knowledge on 29 (58%), had moderate knowledge on 2 (4%) had adequate knowledge on total pre-test. In post-test 0(0%) had inadequate knowledge on, 13(26%) had moderate knowledge on 37 (74%) had adequate knowledge on total pre-test knowledge. Conclusion: Knowledge and knowledge prevention were significant at p<0.01 level regarding upper respiratory tract infections, hence hypothesis is accepted.