This research work concerns with the synthesis and characterization of fatty hydroxamic acid FHA from several vegetable oils namely, corn oil, palm oil, olive oil, soybean oil and sunflower oil. The synthesis of FHA from these vegetable oils was done by three methods, i) from fatty acids FA (carboxylic acid), ii) from methyl/ethyl fatty esters, iii) directly from triacylglyceride. The obtained FHA was characterized by colorimetric, FT-IR and mass spectroscopy. Three clays namely, white kaolin, red kaolin and bentonite were modified by these FHA. These modified clays were characterized by FT-IR, SEM and XRD. The results of all these techniques were verified the modification. The mass uptake experiments were done in acidic and basic media. The results showed that the mass uptake in acidic medium was higher than that in basic medium. The results revealed that the maximum mass uptake was obtained with palm FHA using red kaolin in acidic medium. Generally, the presence of long-chain (mainly 16 and 18 carbon atoms) in FHAs containing O and N atoms suggests that the FHAs should be very useful as surfactants for clay modification.