Two different polyurethanes synthesized from two triols derived from undecenoic acid (PU1) and oleic acid (PU2) fatty acids were functionalised with Collagen type I via plasma treatment aimed at obtaining novel biomaterials with improved biological properties. Scanning Electron Microscopy, X-ray photoelectron spectroscopy, optical microscopy, colorimetric titration methods and contact angle measurements confirmed the surface changes at each stage of treatment, both in terms of morphology and chemical composition. The results for osteoblastic cells (MG63) cultured in vitro proved that PUs modified with collagen had better cytocompatibility that the control PUs. In particular, PU2 displays higher cytocompatibility. (C) 2013 Elsevier Ltd. All rights reserved.