Polyetheretherketone (PEEK) has been widely used to make orthopedic and spinal devices; however, its ability to integrate with surrounding bone tissue has yet to be improved. This study investigated the effect of various surface modifications on biomimetic calcium phosphate formation on PEEK surface. Four different types of surface modifications include roughening by using sand paper, concentrated phosphoric acid (PA), sodium hydroxide (NaOH), and concentrated sulfuric acid (SA, sulfuration). Calcium phosphate mineralization was induced biomimetically by soaking PEEK disks in a modified supersaturated calcification solution (mSCS) buffered at pH 7.4 for 2 days at body temperature (37°C). An alternative mineralization method was also employed by incubating sulfuric acid treated disks with a beta tricalcium phosphate (BTCP) slurry at room temperature. SA had much stronger reaction with PEEK surface than PA or NaOH.  After the mSCS coating process, calcium phosphate mineral formation was consistently found on all the disks. Preliminary scanning electron microscopy and energy-dispersive X-ray microanalysis revealed discrete hemispherical deposits on most disks, consisting of fine calcium phosphate crystals. A thicker, continuous coating was observed on phosphoric acid treated disks. It appeared that delamination occurred more often on the disks with a thicker coating as compared to the disks with discrete deposits. The roughness of the disks did not seem to have an effect on coating formation. The BTCP method seems also promising for the SA treated disks. PEEK surface was successfully mineralized through surface modifications and simple chemistry. Future research is underway to improve coating evenness and adhesion.