The purpose of this study was to provide a comprehensive wear assessment of self mating PEEK-OPTIMA (PEEK) for use in lumbar disc arthroplasty applications under different motion profiles, test frequencies and environmental conditions. Testing of PEEK-on-PEEK disc arthroplasties was performed on a six-station spine wear simulator. The test fluid was newborn calf serum, phosphate buffered saline and 20mM of EDTA with a final protein content of 20 g/l. The loading and motion patterns during the test were modified from ISO 18192-1. The results suggest that self-mating PEEK does not undergo orientation softening at the wear surface. The long term wear properties of self-mating PEEK were found to be relatively low.