When talking about renewable energy sources today, the most important and economical energy sources for Turkey are hydropower and biomass. The present study gives a review of production, consumption, and economics of hydropower and biomass as renewable energy sources in Turkey. Turkey has a total gross hydropower potential of 433 GW, but only 125 GW of the total hydroelectric potential of Turkey can be economically used. By the commissioning of new hydropower plants, which are under construction, 36% of the economically usable potential of the country would be tapped. On the other hand, biomass (wood and wastes) energy is the second most important renewable energy source for Turkey. However, the biomass energy sources of Turkey are limited. In 1998, the biomass share of the total energy consumption of the country is 10%. In this study, the potential of important biomass energy sources and animal solid wastes of the country were determined. The effects of hydropower and biomass usage on the environment were also discussed. Considering total cereal products and fatty seed plants, approximately 50-60 million tons per year of biomass and 8-10 million tons of solid matter animal waste are produced, and 70% of total biomass is seen as being usable for energy. Some useful suggestions and recommendations are also presented. The present study shows that there is an important potential for hydropower and biomass energy sources in Turkey.