In my paper I would like to show that Hegel had a real influence on Friedrich Engels’ way of thinking in his "Dialectics of Nature". Indeed, Engels had a huge knowledge of his time sciences and techniques but also a theoretical frame in which he thought it: Hegel own dialectic of nature. Engels is constantly taking position in relationship to Hegel (for or against) and want in the end to rewrite a new dialectic of nature (he didn’t completed), what we can follow according to his letters. We can also learn that history of science is the real dynamic why Engels refuse or accept theories in Hegel (the most important difference is of course Darwinism; for Hegel, he is clear about it, nature has no history). Seeing the origins of Engels’ thought can help to understand and put it into perspective for the one who would like to thing today’s sciences.