The effects of exposure to extreme heat and cold temperatures on human health have mostly been studied in high-income countries. We examined this association by exploring the effect of extreme temperatures on mortality due to heatstroke and exposure to cold in India and by states. We used temperature data from the Indian Meteorological Department (IMD) and mortality data from the National Crime Records Bureau (NCRB) to examine trends in overall, gender, and age-specific mortality. We used structural breaks analysis to observe changes in India’s mortality trends during 2001–2019. We examined the time trends in the relationship between extreme temperature and mortality for 24 Indian states from 2001 to 2014. We used panel regression and spline regression models. Between 2001 and 2019, India reported 19,693 and 15,197 deaths due to heatstroke and cold exposure, respectively. Top three states with the greatest number of deaths due to heatstroke were Andhra Pradesh, Uttar Pradesh, and Punjab; for cold exposure it was Uttar Pradesh, Punjab, and Bihar. Working-age men were significantly more susceptible to heatstroke. Spline regression results indicated that mortality varied across different temperature bins for both extreme summer and winter temperatures. Our findings demonstrate an urgent need to strengthen welfare and social support systems and invest in built environment and livelihood interventions to counter the avoidable mortality from extreme temperature events.