Experiments were conducted at Clayton and Rocky Mount, NC in 1995 and at Lewiston, NC in 1997 to investigate weed control, crop response, and yield of Roundup Ready cotton (Gossypium hirsutum L.). Weed management systems consisted of the following herbicide combinations: Treflan applied preplant incorporated (PPI) at 0.5 lb ai/ac with Cotoran preemergence (PRE) at 1.25 lb ai/ac alone or followed by (fb) 1) Cotoran at 1.0 lb/ac plus MSMA at 2.0 lb/ac early post-direct (EPDS) alone or fb Bladex at 1.0 lb ai/ac plus MSMA at 2.0 lb/ac at LAYBY, 2) Roundup early postemergence (EPOST) at 0.75 lb ai/ac alone or fb Bladex plus MSMA at LAYBY, 3) Staple at 1.0 oz ai/ac EPOST alone or followed by Bladex plus MSMA at LAYBY. Other systems evaluated included Treflan PPI fb Staple EPOST alone or fb Bladex plus MSMA LAYBY, and Cotoran PRE fb Roundup EPOST alone or fb Bladex plus MSMA LAYBY. Additional systems evaluated were Roundup applied EPOST alone or fb Bladex plus MSMA LAYBY; Cotoran PRE fb Roundup alone or fb Bladex plus MSMA LAYBY; and Treflan PPI plus Cotoran PRE fb Roundup as needed. For Roundup as needed systems, Roundup was applied EPOST over-the-top and then applied post-directed under a spray hood twice if residual soil-applied or LAYBY herbicides were used in 1995; while three applications of Roundup were post-directed under the spray hood in 1997 when no residual herbicides were used. There was an untreated check for comparison. All POST and Roundup treatments included a nonionic surfactant at 0.25% and 0.5% respectively in 1995, while only POST treatments used a nonionic surfactant in 1997. An unknown variety provided by Monsanto was planted in both studies in 1995 while Paymaster 1330RR was planted in 1997.