Introduction: Maternal undernutrition plays a critical role in influencing maternal, and child health outcomes and magnifies the risk of death of the mother at the time of delivery. High-risk fertility behaviour is an obstacle to tackle maternal and child mortality. Objectives: The aim of this study is to understand the level of high-risk fertility behaviour and chronic undernutrition among ever-married women, and also to examine the association between the two. Methods: Data for 190,581 ever-married women (15–49) giving at least one birth during five years prior to the National Family and Health Survey (2015-16) was used. Descriptive statistics and modified Poisson regression were applied to examine the association between high-risk fertility behaviour and chronic undernutrition. Results: Results show that 24% women were undernourished and 32% were subject to have at least one of the high-risk fertility behaviour. Collectively, 26% and 6% of the women were susceptible to single and multiple high-risk behaviour, respectively. After adjusting sociodemographic backgrounds, results showed a significant association between high-risk fertility behaviour and chronic undernutrition. As such, 5% of women were likely to be undernourished due to high-risk fertility behaviour on the whole, and 4% and 6% of the women, respectively, were likely to be undernourished due to single and multiple high-risk fertility behaviour. Conclusions: This study finds that maternal high-risk fertility behaviour is an important factor in increasing the likelihood of women to be in a state of chronic undernourishment. Therefore, policy and programme should be implemented to reduce high-risk fertility behaviour among Indian women.