The foundation of cotton production is establishing a uniform, vigorous, and healthy stand. Cotton seed and seedling diseases reduce stand and vigor, and affect plant health, yield and fiber quality. The main pathogens are Pythium ultimum, Rhizoctonia solani, and Thieloviopsis basicola which cause seed and seedling root rot, and pre- and post-emergence damping-off. Cultural practices, seed and soil fungicides, and host resistance are used to control the disease complex. The biocontrol agent Gliocladium virens parasitizes R. solani and inhibits P. ultimum by antibiosis. Ten tests were conducted in Texas over a three year period (1990-1992) to determine the effects of biological control with G. virens strains, singularly or in mixtures, and in combination with fungicides, on cotton seedling emergence and survival, lint yield, and fiber quality traits of Stoneville 213 under field conditions. The influence of carrier and seed sticker also were studied. Seed treated with G. virens strains produced stands, lint yield, and fiber quality similar to that produced by the fungicide treated seed, and significantly higher than the nontreated control. G. virens strains differed in their effectiveness as biocontrol agents, and when used in combination with fungicides, specific strains were compatible. Moist millet was more effective as a carrier than wheat bran. Generally, latex was more effective as seed sticker than opadry. G. virens strains in combination with low rates of fungicides should be effective in controlling cotton seed-seedling pathogens, and improve plant health and productivity.