The coupling of a biological sensing element (such as antibodies, enzyme or cells) with a transducer, either electrochemical, optical or piezoelectric, is the basis of biosensor. The two crucial components of the biosensor are usually integrated by the immobilization of the biorecognition molecule onto the surface of the transducer. Immobilization of the biomolecule is a particularly demanding aspect of the fabrication of the biosensors as the immobilization procedure must maintain the biorecognition molecule close to the transducer surface, while retaining its biological activity, a reproducible manner. The use of self-assembled monolayers (SAMs) can potentially provide a reproducible and robust method of fabrication immobilized antibodies layers where some control over the orientation and distribution of the antibodies is afforded. The aim of this work is to specifically study on the antibody orientation at L-lysine SAM modified aluminum supports. The SAM modified aluminum support was prepared by incubating 10mM 3-Mercaptopropionic acid (3-MPA) in ethanol for 2h at room temperature. For the coupling of antibodies, the surface was treated with 50mM 3-(dimethylamino-propylethyl)-N-ethylcarbodiimide/ 50mM N-hydroxysuccinimide in PBS (pH 5.0) for 30 min followed by incubation 0.1% (w/v) lysine in PBS, then a solution 1 m g/mL of immunoglobulin G (IgG) was incubated for 30 min. In order to block the other reactive sites, 1% (w/v) bovine serum albumin solution was used for 30 min. In comparison to the control, the use of lysine was better the antibodies orientation, and the average of absorbance measure was twice more than the control (without lysine). In addition, the pH effects were also evaluated showing best results at pH 9.6. Finally, these results showed the lysine at SAM modified metallic surface can improve the immunosensing electrode performance.