This chapter discusses various techniques for measuring intrinsic surface diffusion, mass transfer surface self-diffusion and mass transfer hetero surface diffusion. Field ion microscope (FIM) is an ideal technique for observing intrinsic surface diffusion of isolated adatoms on a small perfect surface. The other techniques used for measuring intrinsic surface diffusion are field electron microscope (FEM), scanning electron tunneling microscope (STM) and relaxation measurements. Intrinsic surface self-diffusion can also be studied by quasielastic scattering of low-energy He atom. Techniques for measuring mass transfer surface self-diffusion are: i) radio-active tracer technique (RAT), in which a source of radio-active material is deposited on a flat surface, ii) capillarity techniques, for which the clean surface has to be perturbed from its lowest energy configuration in order to cause a mass flow at elevated temperatures from which a surface self-diffusion coefficient can be extracted and iii) STM which is not only capable of imaging single atoms or small clusters on flat surfaces but also larger irregularities. Techniques for measuring mass transfer hetero surface diffusion are i) RAT whose principle is same as for surface self-diffusion, ii) scanning techniques which can apply to typical surface diffusion geometry of an initial localized source of diffusing material A on a well-defined substrate surface B, iii) laser induced thermal desorption (LITD) which is suitable for relatively weakly adsorbed atoms or molecules on metal surfaces and iv) FEM which are used to image the diffusion front of an adlayer of atoms or molecules advancing across a region of clean surface.