Amorphous silica is an interesting material regarding the possibilities of modification in relation to silica gel considering its low cost and no need of surface activation previously to modification procedures. This paper describes the modification of an amorphous silica with 2-benzothiazolethiol and 2-mercaptoimidazole. After derivatization the modified silica was characterized by elemental analysis, IV, NMR (H-1, C-13 and Si-29), BET, thermal analysis (TG and DSC), and SEM.