This study has been carried out to investigate the processing parameters affecting polyetheretherketone's (PEEK) spinnability in a melt spinning process. PEEK has excellent mechanical and thermal properties and fibers made from it could be used in extreme environments. Different PEEK grades were characterized thermally and rheologically to see which one is the most suitable for fiber spinning. The spinning tests made with the most suitable grade (Victrex 151G) show that increased processing temperature, increased capillary diameter or shorter spinning path length improves spinnability. The best fibers made in optimal processing conditions (400 degrees C temperature, 30/1 mm capillary, and 5 cm spinning path) were 18 mu m in average diameter. Because of the limitations of the system used, variations in fiber thickness were noticeable and worsened the spinning stability. Scanning electron microscope photos confirmed these variations, and they were also visible in an optical microscope. The selected low-viscosity PEEK grade provided good spinnability but gave filaments with only mediocre mechanical properties, the tensile strength being around 280 MPa. (c) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012