Layer-by-layer (LBL) self-assembly is one of the most popular methods for the preparation of multifunctional nanostructured thin films. This technique is primarily based on the sequential adsorption of oppositely charged compounds due to attractive electrostatic interactions, however other molecular interactions (i.e. hydrogen bonding, hydrophobic, or covalent bonding) can mediate the self-assembly process. Recently, our group has reported the successful synthesis of a series of novel redox polymers based on the attachment of ferrocene redox centers (Fc) to linear poly(ethylenimine) (LPEI) that are able to produce high current responses (> 1 mA/cm²) with a variety of enzymes (e.g. glucose oxidase, fructose dehydrogenase, laccase, and horserardish peroxidase). Based on their high current densities and the high density of amine groups they appear to be excellent candidates for LBL assembly. In this presentation we will describe the development, characterization and application of nanostructured films based on both electrostatic and covalent layer-by-layer assembly of redox polymers, biological molecules (e.g. enzymes, polysaccharides), and single-walled carbon nanotubes as a versatile means to produce functional coatings for biosensing and biofuel cell applications. When LBL assembly is employed to fabricate nanostructured composites of ferrocene redox polymers (Fc-LPEI) and glucose oxidase, current densities of 1.4 mA/cm² are produced in response to glucose. Likewise these films can produce power densities of ~150 μW/cm² when incorporated into biofuel cells as bioanodes. In this presentation we will also discuss the effects of redox polymer structure, LBL washing procedures, and solution pH during LBL assembly on the structure and performance of these films.