INTRODUCTION: Cardiac disease in pregnancy is a major cause of maternal mortality and morbidity in women, particularly in resource limited countries like Nepal. Rheumatic Heart Disease is the commonest cardiac disease complicating pregnancy. There is very limited data and evidence from Nepal regarding rheumatic heart disease complicating the pregnancy. The study aims to find out the prevalence of rheumatic heart disease among cardiac disease patients in a tertiary care hospital. METHODS: A descriptive cross-sectional study was conducted among 41 women with cardiac disease who delivered babies at Chitwan Medical College from 1st January 2018 to 31st December 2019, after taking ethical approval from the Institutional Review Committee. A convenient sampling method was used. Statistical Package for the Social Sciences was used for data analysis. Point estimate at 95% Confidence Interval was calculated along with frequency and proportion for binary data. RESULTS: Among 41 pregnant women with cardiac disease, 32 (78%) (95% Confidence Interval = 65.32-90.68) had rheumatic heart disease. The mean age of the affected pregnant women was 24.9±4.49 years. Out of 32 patients with rheumatic heart disease, postpartum haemorrhage was the most common maternal complication 5 (15.6%) followed by hypertension 4 (9.7%). CONCLUSIONS: Rheumatic Heart Disease was highly common among pregnant women with cardiac disease.