Climate change is significantly impacting the river systems of India, affecting river hydrology, ecosystem dynamics, water quality, and water temperature. This chapter deals with the negative impacts of climate change, including the physical, chemical, and biological characteristics of Indian rivers. As a result of the frequency of extreme events and alterations in precipitation patterns, changes in river flow regimes have occurred. In the Himalayas, Glacier melting is one of the principal causes that enhanced river flow at first, but eventually, diminished the water supply. Aside from elevated temperature, altered rates of evapotranspiration considerably modify river base flows. Reduced river flows induce in the concentration of contaminants, which boosts the likelihood of eutrophication and geomorphological alterations, i.e., sediment load and soil erosion, altering the river course. Increasing water temperature due to climate change is causing dissolved oxygen (DO) reduction and altered seasonal behavior, which has cascading effects on the aquatic ecosystems. All of these together bring major impacts on agriculture, water security, livelihoods, and communities. Further, this chapter presents the imperative requirement of formulating strategies and policies for safeguarding such vital river systems by determining the climate change impacts on rivers.