We have studied the effect of application of growth regulators, (2-chloroethyl) trimethylammonium chloride (CCC), N,N-dimethylaminosuccinamic acid (SADH), gibberellic acid (GA3) and 3-indoleacetic acid (IAA) on cotton, Gossypium hirsutum L. cv. 'IAC-RM3', in relation to atack of Aphis gossypii Glover, 1876, under greenhouse conditions. Two determinations of infestation levels of the aphids showed differences in degree of infestation among treatments. CCC treated plants showed increasing in aphid colonization in relation to GA3 at 100 ppm treated plants. The application of SADH at 4000 ppm also showed a tendency of increasing aphid colonization in relation to treated plants with GA3 at 100 ppm. Probably growth retardants promote differences in the water status of hostplant; and the aphids preferences to that plants suggest that the increase in the osmotic potential promotes better rates of aphid feeding than GA3 treated plants. In treated plants with GA3 at 100 ppm the infestation decreased, there was water stress during the warmer time of the day and a probable decreasing in the osmotic potential.