Different adsorption isotherms such as the Gibbs, Szyszkowski,Frumkln and Temkin and polynomial were found as fits well to experimental interfacial tension isotherms for 2-hydroxy-5-alkylbenzaldehyde oximes at octane/water and xylene/water interfaces. The values of surface excess computed according to them increase as the length of the alkyl chain length increases for xylene/water system. Different behaviour was found at octane/water interface.