Cellulose-based nanocomposites could potentially function as structural materials for prosthetic vascular conduits given their moldability, mechanical strength in the wet state, stability, and durability as well as their ability to integrate a nanofibrous porous network with superior structural diversity and functional versatility. In this study, we have developed a cellulose-based nanocomposite consisting of cellulose nanowhiskers (CNWs) embedded and aligned in a cellulose acetate propionate (CAP) matrix. When compared to non-biocompatible inclusions such as carbon nanotubes and Kevlar fillers, CNWs imparted significant strength and directional rigidity to the CNW-CAP composite even at 0.2 wt%. In addition, a significant improvement in critical properties was observed when the CNWs were aligned in an externally-applied relatively weak magnetic field (0.3 T). Magnetically induced alignment not only improved the directionality and percolation limits of the nanoparticles within the medium, but also drastically lowered the optimum amount of CNWs required to obtain the best composite performance. Therefore, highly desirable properties can be induced in cellulose-based biocompatible composites by modifying the processing methods, with potential use as scaffolds for vascular tissue engineering of a small diameter graft. (C) 2013 Elsevier Ltd. All rights reserved.