Abstract: Postnatal stress urinary incontinence (SUI) is an important social and hygienic health problem affecting between 3% and 24% of adult women. This study was conducted to determine the effectiveness of antenatal exercise on postpartum women who were identified with SUI during their third trimester pregnancy. Among 103 women attending antenatal clinic of Dhulikhel Hospital, 34 women were identified with SUI during their third trimester pregnancy. They were treated by physiotherapist with antenatal exercise including education and home exercises. After 6 months, a telephone survey was conducted to find out the results of the treatment given during the antenatal period. Only 27 respondents answered the telephone survey. From these respondents, only 37% women had continued exercises where as 63 % of the women did not continue to do exercises even after identifying the problem. All women who continued the recommended exercises were found to have no SUI whereas SUI had reoccurred in 70% women who discontinued exercises. A very significant (p=0.00) association was found between antenatal pelvic floor muscle exercise, prevention and treatment of SUI indicating that pelvic floor exercise helps prevent SUI during antenatal period. Awareness of the importance of Pelvic floor exercise should be promoted especially in developing countries like Nepal which offers a cost effective management and improve the quality of life.