Experiments were conducted in 2004 through 2007 to evaluate weed management systems in twin-row cotton. Glyphosate tolerant cotton was planted in twin-row (19 cm apart) and single-row planting patterns (76 cm apart) with final plant populations of 3, 6, or 12 plants/m. Weed management regimes included one, two or three herbicide applications.  Weed control with the lowest level of herbicide input was up to 10% better in the twin-row cotton and at the higher cotton density than in the single rows and at the lowest density of 3 plant/m.