This paper discusses several methods used by the Bureau of Reclamation for the undisturbed sampling of soils including open-drive piston and double-tube core-barrel sampling. The paper describes in general terms how research studies have resulted in techniques now standardized. Included are recommendations for sampling saturated and unsaturated soils; expansive and nonexpansive materials; and loose, alluvial, and colian soils. An important consideration is the method by which the holes are stabilized with drilling mud.