Conservation tillage cotton rotation systems can reduce cotton production costs, increase yields, and reduce soil erosion for the sandyland areas of the Texas Southern High Plains. New weed control systems have been evaluated to replace tillage operations and thus maintain crop residues on the soil surface. Studies were established in 1986 and 1987 on a fine sandy loan soil near Brownfield, Texas to evaluate preplant and preemergence weed control in a conservation tillage sorghum-cotton rotation. Treatments evaluated as preplant application for control of winter weeds including horseweed [Conyza canadensis (L.) Cronq.] were 2,4-D . Most effective horseweed control was achieved with 2,4-D, dicamba, and glphosate + 2,4-D. Most effective horseweed control was achieved with 2,4-D, decamba, and glyphosate + 2,4-D. Preemergence treatments for pigweed (Amaranthus hybridus L.) and volunteer sorghum (Sorghum bicolor L. Moench) control included methazole, dipropetryn, prometryn, diuron, metolachlor, and glyphosate + 2,4-D. Preemergence treatments for pigweed d(Amaranthus hybridus L.) and volunteer sorghum (Sorghum bicolor L. Moench) control included methazole, depropetryn, prometryn, diuron, metolachlor, and metolachlor combinations. All treatments were followed by sprinkler irrigations. Effective pigweed and volunteer sorghum control was, achieved with higher rates of methazole, dipropetryn, and metolachlor combinations. Significant cotton injury was observed from metolachlor ( alone or in combinations) and higher rates of prometrym. Higher cotton yields resulted with applications of dipropetryn applied at 4.4 kg/ha where excellent season-long weed control was achieved with no crop injury.