Seedlings of cotton were treated 15 days after germination, with (2-chloroethyl) trimethylammonium chloride (CCC) at concentrations of 20, 200 and 2,000 ppm and the check to verify the effect of the compound on the growth of the plant. The experiment was done under greenhouse conditions in 1974. The main proposal of this work is to study the variation of plant height, percentual plani variation height, net assimilation rate, relative growth rate and the leaf area ratio with application of CCC. The growth regulator promotes decrease in plant height and in percentual plant variation height, 6 and 12 days after application of CCC. CCC at concentration of 2,000 ppm causes, 12 days after spray, the inferior heights and fewer percentual variation heights in cotton plants. Application of CCC at concentrations of 20, 200 and 2,000 ppm, promotes proportional diminutions in the net assimilation rate, relative growth rate and in the leaf area ratio in relation to check.