Electrochemically synthesized anodic aluminum oxide (AAO) is one of the most attractive candidates to be used as a multifunctional nanostructured surface matrix. This ceramic membrane is a self-ordered nanoporous array that is suitable for many technical applications. Based on above background, the aim of this work was to develop methods of surface modification of the Anodisc^TM membrane filters with either polyaniline (PANI) or polyethyleneimine (PEI) and to propose the obtained composites as supports for biomolecules immobilization. The AAO/PEI composite was prepared by cross-flow filtration of the polymer solution through the membrane. AAO/PANI was synthesized using surface chemical polymerization performed in nitric acid solution of aniline and permanganate as oxidizer. After glutaraldehyde activation, Horseradish peroxidase and trypsin were immobilized on the composites. The immobilized enzymes on composites had their activities determined either batch wise or flow-through system. The AAO/PEI-trypsin derivative yielded filtering membrane catalytically active with initial velocities of 2.95nmol.min^-1 and 3.8nmol.min^-1 assayed in batch mode and flow-through system (0.46mL.min^-1), respectively. Flow limitation caused by PEI film was overcome using ascending flux and scanning electron micrographs showed that the pores were clogged in a great extent. Furthermore, AAO/PEI-trypsin prepared with membranes of different porosities showed that the enzymatic activity increased as the inside diameter of the pore enlarged. Additionally, it was demonstrated that covalent coupling showed higher activity as compared to attachment by adsorption on a membrane without PEI functionalities, which had 2.9 times less activity. Horseradish peroxidase was successfully immobilized onto the AAO/PANI and retained 74% of its initial activity after six batch cycles and 98% following 24 minutes under 0.9 mM H₂O₂ continuous flow. It was also observed by electron microscopy that membrane pores remain intact after derivatization with polyaniline. Therefore, these results showed the viability of these composites for enzyme immobilization, but they also revealed the importance of adequate AAO functionalization to produce minimal changes in the nanostructured feature of the membrane.