With this paper we intend to present some aspects of the relationship between philosophy and science in Heidegger’s thought. The reflexion on the limits of science as a human behavior and its roots in a deeper ontological ground always occupied an important place in Heidegger’s work. In Being and Time the author connects the scientific behavior to a theoretical and objective visualization and demonstrates the derivative character of this theoretical visualization itself with regard to a more immediate contact to beings. The philosophy, on the other side, is also structured as a theoretical behavior, but it would have, as a distincitve feature, a tendency to the contemplation of the world in a totality. What this distinction implicates to the relationship between philosophy and science and in what extent the second finds its ontological fundaments in the first will be treated in this work. Lastly, we intend to indicate that the idea of the ontological difference between being (Sein) und beings (Seienden) is the ground of the relationship between philosophy and science.