Field studies were conducted in 1998 and 1999 near Lubbock, TX to evaluate weed control in Roundup Ready cotton produced in conventional and conservation tillage (terminated wheat cover) systems. Treatments included preplant incorporated (PPI) and preemergence (PE) herbicides applied alone or in combination with Roundup Ultra (glyphosate) applied postemergence-topical (PT) and postemergence-directed (PD) compared to Roundup Ultra applied alone. Paymaster 2326RR cotton was planted in both systems in 1998 and 1999. A shielded sprayer was used for PD applications. Visual weed control ratings were made during the growing season and cotton lint yields were determined.