Applications of microwave measurement techniques, including frequency-domain and time-domain methods, for determining the permittivity of agricultural products (seeds, plants, grains, fruits, meat, etc.) are reviewed. Graphical data illustrating the dependence of the dielectric constants and loss factors of such products on moisture content, frequency of the applied fields, temperature, and bulk density of granular materials are provided for selected materials. Finally, recommendations are offered for further study and applications of permittivity measurements.