Superconductivity at 17 K was observed in a potassium (K)-doped fullerene nanowhisker (K-C60NW). The superconducting volume fraction of a full shielding volume was as high as 80% in the nominal composition of K3.3C60NW, while that of K-doped fullerene powder was less than 1% under the same heating condition at 200 degrees C. We report the superconducting behaviors of our newly synthesized K3.3C60NWs, such as the applied field dependence of magnetization and the critical current density of 3 x 10(5) A/cm(2) at 5 K under 50 kOe, in comparison to those of K-doped fullerene powders. (c) 2012 Elsevier Ltd. All rights reserved.