Field experiments were conducted at the Experimental Farm, Department of Agronomy, Annamalai University, Annamalai nagar to study the evaluation of Pendimethalin 38.7% CS and various cotton herbicides in cotton during with cv. MCU 7. The experiment consists of eight treatment viz., Pendimethalin 38.7 % CS @ 438.75 g a.i/ha, Pendimethalin 38.7 % CS @ 580.50 g a.i/ha, Pendimethalin 38.7 % CS @ 677.25 g a.i/ha, Fluchloralin 45% EC @ 1125 g a.i/ha, Pendimethalin 30 % EC @ 750 g a.i/ha, Trifluralin

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... 8% EC @ 960 g a.i/ha, Fluchloralin 45% EC @ 2000 g a.i/ha and unweeded check. Regardless of season, all the treatments were found to significantly influenced the weed biometrics, growth, yield components and yield of cotton. Among the treatments tested, Pendimethalin 38.7 % CS @ 677.25 g a.i/ha recorded least weed counts, weed dry matter production, highest weed control index and weed control efficiency favouring higher growth, yield attributes and seed cotton yield in first and second seasons, respectively. This was followed by Pendimethalin 38.7 % CS @ 580.50 g a.i/ha. These treatments were significantly superior than the rest in reducing the weed infestation and ultimately increasing seed cotton yield in both seasons. Unweeded check recorded the highest weed counts, weed biomass resulting in the least growth and seed cotton yield in first and second seasons, respectively. From the study, it may be concluded that application of Pendimethalin 38.7 % CS @ 677.25 g a.i/ha is considered to be judicious recommendation to cotton farmers in view of inadequate labour and higher manual weeding cost.