In my thesis I will deal with the outstanding significance of President Theodore Roosevelt in the conservation movement at the turn of the century and I will examine the activities of a man who made the idea of protection of natural resources, preservation of wilderness, safeguard of wildlife and wise land management essential to America's progressive future. In what follows I will shed light on the fact that Roosevelt was influenced by many people who turned his attention to the importance of wilderness and wildlife protection and helped him develop this immense passion for nature. He was also aware of the fact that the protection of beautiful natural gems and the national parks can only be realized if everyone considers it a national duty. To this end he made innumerable public speeches during and even after his presidency to raise awareness for conservation and respect for nature. I will also deal with the question how Roosevelt used his executive power to overcome obstacles which were mostly caused by the uncompromising Congress that made it an even more challenging a task for Roosevelt to carry out his conservationist program and secure America's progressive future. Furthermore, I will examine the crucial elements in his conservation policy concentrating mainly on water conservation, the safeguard of wildlife and wilderness and wise forest management and protection.