The mechanical properties of oil shale are being investigated to provide the basic information necessary to develop and optimize procedures for modifying the rock in place, as required by diverse production techniques. A method is devised where Poisson's ratio, Young's modulus, and ultimate tensile strength along the bedding planes can be obtained on oil shale samples (oil shales are slightly anisotropic) from a split cylinder test. Stress and vertical and horizontal strain measurements on 40 oil shale samples from the Tipton Member of Wyoming's Green River Formation were used to calculate mechanical properties. The determined mechanical properties show strong linear relationships to the volume of organic matter in the oil shale but little relationship to the major matrix mineral, dolomite. Relationships developed are sufficiently precise to provide useful estimates of oil shale's mechanical properties from the organic volume.