Technical Abstract: Cover crops, usually grown after the harvest of main crops in the fall to provide vegetative cover for reducing soil erosion, have many benefits in improving soil and environmental quality, besides sustaining crop yields. Cover crops use residual soil N and reduce NO3-N content in the soil profile, thereby decreasing the potential for N leaching. Cover crops supply additional biomass residue to soil, increase organic matter, improve soil properties, and sequester atmospheric CO2, thereby reducing the potential for global warming. Legume cover crops fix N from the atmosphere and supply N to the succeeding crops, thereby reducing the rate of N fertilization. As a result, they increase succeeding crop yields and quality compared with nonlegume or no cover crops. In contrast, nonlegume cover crops are effective in increasing soil organic matter and reducing N leaching compared with legume or no cover crops. Ideal cover crops that provide all these benefits, i.e. to supply N, increase soil organic matter, maintain crop yields, and reduce residual soil N are needed to sustain crops yields and improve soil and environmental quality. Bicultural legume-cereal cover crop combination is one of those cover crops that can provide most of these benefits. Studies have shown that biculture of legume, such as hairy vetch (Vicia villosa L.) and nonlegume, such as cereal rye (Secaele cereale L.) can coexist together, thereby supplying increased above- and belowground biomass and C and N contents, which increased soil organic matter and C and N sequestration compared with monoculture cover crops. The hairy vetch + rye biculture reduced residual soil profile NO3-N and sustained N supply and cotton (Gossypium hirsutum L.) and sorghum [Sorghum bicolor (L.) Moench] yields and N uptake compared with hairy vetch alone. This review will evaluate the performance of legume-cereal (hairy vetch + rye) bicultural cover crops, their above- and belowground biomass yields and C and N contents, and their effects on soil C and N levels and crop yields compared with monocultures (hairy vetch or rye) or the no cover crop treatment.