Implantation of dental and orthopaedic devices is affected by delayed or weak implant-bone integration and inadequate new bone formation. Innovative approaches have been sought to enhance implant-bone interaction to achieve rapid osseointegration. The aim of this study was to develop biomimetic polypeptide nanocoatings and to evaluate cell adhesion, proliferation, morphology, and biocompatibility of polypeptide nanocoatings on implant surfaces. A recently developed nanotechnology, i.e., electrostatic self-assembly, was applied to build polypeptide nanocoatings on implant models, i.e., stainless steel discs. Our in vitro tests using human osteoblast cells revealed that substantially more (one order magnitude higher) osteoblast cells were attached to polypeptide-coated, stainless steel discs than to uncoated discs within the first few hours of contact. The developed biomimetic nanocoatings may have great potential for dental and orthopaedic applications.