Nanofibers of YOF doped with trivalent lanthanide ions (Ln(3+)) have been synthesized successfully via an electrospinning method combining with high-temperature calcination in air. Scanning electron microscopy (SEM) observations showed that the nanofibers had uniform one-dimensional (1D) morphology. X-ray diffraction (XRD) analysis and transmission electron microscopy (TEM) images revealed that the calcined fibers were constituted by rhombohedral phase yttrium oxyfluoride nanocrystals. Under the excitation from a 980 nm laser diode, YOF:Yb3+,Tm3+ and YOF:Yb3+,Er3+ fibers emitted blue and red light, respectively. Upconversion mechanisms of these YOF:Ln(3+) fibers were also discussed in detail. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.