The improvement of California's highway system to meet modern standards of grade and alignment frequently forces the line into deep cuts or high fills. The sites of proposed cuts are studied carefully, and when feasible soil borings or core drill holes are made. Designs of cut slopes in the California highway system are developed on the basis of soil mechanics, geological studies, laboratory tests, experience, and judgment. An effort is made to avoid serious slides; but the variable nature of most earth and weathered rock formations often leads to slim margins of safety in cut slope design. As a consequence, failures sometimes do occur. This report describes several important cuts that have been required in the past few years for the construction of California highways. They represent a wide range in conditions and performance and emphasize the difficult problems that must be faced by highway designers and builders.