In the textbook are presented the fundamental principles of heat transfer by conduction, convection, and radiation; mass transfer by diffusion and convection. Application to engineering situations. The textbook presents an exhaustive coverage of the theory, definitions, formulae and examples which are well supported by plenty of diagrams and problems in order to make the underlying principles more comprehensive. The textbook is intended for use in the educational process in the preparation of bachelors in specialty 185 «Oil and Gas Engineering and Technology»), and can also be useful for masters, graduate students, researchers and specialists.