Mapping mortality impacts of the projected climate in urban areas of developing countries will play a crucial role in instituting planned adaptation measures to protect public health. We provide a comprehensive assessment of mortality in 52 urban areas (population >1 million) that are located in diverse climactic regimes in India. To understand implications of the climate warming on heat wave mortality in the urban India, we used downscaled and bias corrected temperature projections from the Coupled Model Inter-comparison Project Phase 5 (CMIP5) models. Using the observed data for the period of 2005-2012, we developed temperature-mortality relationships using Poisson regression models for the selected urban areas in India. These relationships were applied to future temperature projections from the 23 CMIP5 models for the summer and winter seasons for the Representative Concentration Pathway 4.5 and 8.5 scenarios. Here we show that urban areas in India are projected to witness two-fold or more increases (p <0.05) in heat related mortality (i.e. summer season) under the projected future climate. Mortality is projected to increase 71and 140% in the late 21st century under the RCP 4.5 and 8.5 scenarios, respectively. Moreover, we find that increases in the heat related mortality will overshadow declines in the cold related mortality (winter season). Moreover, urban areas of Delhi, Ahmedabad, Bangalore, Mumbai and Kolkata are projected to experience the highest absolute increases in the heat related mortality in 2080s under the RCP 8.5 scenario. Our findings underscore the need for Indian policy makers to anticipate, plan and respond to the challenge of climate change.