Abstract: The adsorption of a series of ethoxylated nonionic and anionic surfactant molecules at aqueous / air interface at different temperature ranges [298, 308, 318, 328 and 338K] was studied. Different surface parameters were evaluated from surface tension measurements at different temperatures. The effectiveness of adsorption, Гmax, for all nonionic and anionic surfactants was discussed with respect to their hydrophilic and hydrophobic characters.