Ohio soils used as subgrade soils for a road were studied to evaluate parameters affecting resilient modulus. The dominant Ohio soils could be classified in one of three AASHTO Soil Classification system groups, A-4, A-6, and A-7. Laboratory tests were performed on the cohesive soils to measure Atterberg Limits, particle size, optimum moisture content, maximum dry density, and unconfined compressive strength. The resilient modulus tests were conducted on each sample compacted at the dry of optimum, optimum, or wet of optimum moisture content. The measured resilient modulus for each soil sample was analyzed to evaluate the effect of stresses and engineering indexes. Three different models to predict the resilient modulus using engineering indexes were used to compare the measured resilient modulus. The confining stress affected the resilient modulus. The resilient modulus decreased with an increase in the deviator stress, and linearly increased with an increase in the percent of silt and clay and maximum unconfined compressive strength. The increase in moisture content considerably affected the decrease in the resilient modulus. The resilient modulus predicted using the three models showed a large variation with the resilient modulus measured.