Engineers have often questioned whether the shear characteristics of soils compacted in the laboratory are comparable to the shear characteristics of the same soils compacted by field construction methods. A program to provide comparative data was initiated by the Bureau of Reclamation in 1959. Duplicate cubic-foot blocks of soil were excavated from impervious zones of three earth dams. Laboratory triaxial shear tests were performed on (1) undisturbed specimens cut from these blocks, (2) specimens of the soil molded by the standard impact method, and (3) specimens cut from a block of the same material remolded in the laboratory sheepsfoot compactor. This paper presents the results of the tests performed on these samples.