In the article, mainly based on the reference to the entries in the diary of Th. Dobzhansky, a geneticist and one of the founders of the “synthetic theory of evolution”, examines how Dobzhansky tried to combine science, primarily evolutionary theory, and religion. It is argued that although Dobxzhansky was a believer during whole his life, he became a peculiar believer who revised for himself and for others the former, primarily religious answers to the “ultimate questions” of existence, and posed these questions in a new, evolutionary way. Even more, he tried to substantiate and justify religion and his belief in God through the evolutionary theory, to demonstrate that science and religion are not incompatible, and to offer his believe in the usefulness of science and religion to each other. This Dobzhansky's attempt was perceived and evaluated ambiguously by both scientists and religious figures. In addition, Dobzhansky owing to his search for these answers, made a number of world outlook and general cultural conclusions for himself and presented these conclusions in articles and books written not only for colleagues in the scientific community, but also for other people.