The most frequently reported adverse affect of preplant incorporated dinitroaniline herbicides on cotton has been the inhibition of lateral root formation in the treated layer of soil. A yield analysis of public and private trial data from the Southeastern U.S. was made for the years 1973 through 1985 to observe herbicide effects on cotton yield. Results indicate that cotton treated with pendimethalin yielded an average of 25 lbs. of lint per acre more than trifluralin treated cotton. The difference in yield may be due to a greater cotton seedling tolerance to pendimethalin. This tolerance allows for cotton seedlings to have stronger root development and greater resistance to weather stresses.