Cotton is a wide spaced and initial slow growing crop and therefore offers scope for intercropping green manure. Intercropping and incorporation of green manure supply nitrogen and increase the nutrient use efficiency and yield of cotton. Incorporation of leguminous green manure crops has the beneficial effect on soil fertility also. Green manure intercrop serves as plant protectant too. To start with green manures effect on the associate cotton growth and yield are reviewed hereunder followed by their effect on soil fertility, pest and weed control on the principle crop. © 2010 Asian Network for Scientific Information.