The wear characteristics of MBOCA based polyurethaneureas and ETHACURE 300 based polyurethaneureas of two different hardnesses have been investigated and compared. Evidence of abrasive and interfacial wear mechanisms were present in all materials but to different degrees depending on the material. Two levels of effect were apparent in terms of determining wear resistance. Firstly the softer materials displayed better wear resistance compared to the harder based materials. Secondly, MBOCA based materials displayed better wear resistance compared to ETHACURE 300 based materials. A second batch of ETHACURE 300 was produced and was found to have better wear resistant properties. Chemical analysis revealed that crosslinking was present in the second batch of ETHACURE 300 based polymer but not present in the first batch. Structural and mechanical analysis revealed that the combination of crosslinking and MBOCA curative structure produced a polymer morphology that tended to improve wear resistance in slurry based environments. Crosslinking appeared to induce a less phase separated system with more interpenetrating soft segments in the hard domains, while the MBOCA curative structure displayed less steric hindrance than the ETHACURE 300 curative which allowed for a more ordered polymer backbone. Hysteresis was found to be sensitive to the domain morphology and degree of crosslinking and as such appeared to be a good indicator of wear resistance for these materials. In an effort to improve wear resistance of ETHACURE 300 materials, modifications were made to the polymer structure by varying the stoichiometric ratio to produce polymers with different amounts of chemical and physical crosslinks. All materials displayed a reduction in wear in a slurry environment compared to the original ETHACURE 300 polymer. Evidence of abrasive and interfacial wear were present in all materials. Additionally, fatigue wear was present in the most heavily crosslinked polymer. Structural and mechanical characterisation indicated that the crosslinked systems were less phase separated with more interpenetrating soft segments in the hard domains. Moreover, crosslinking the polymer increased hard domain melting temperature which helped reduce the degree of wear. Hysteresis results confirmed the correct order of wear for these materials.