Ultra-high molecular weight polyethylene (UHMWPE) is widely used as joint replacements because its low friction coefficient, relatively good thermal stability, low toxicity, bioinertness and relatively good wear resistance, with respect to other polymers [1-3]. It is well understood that the physical, chemical and mechanical properties of crystalline polymers depend on the morphology, the crystalline mass fraction and degree of cross-linking [4]. In this study it is aimed to improve the mechanical and crystalline properties of UHMWPE with the addition of nano sized TiO2 particles with the amount of 0.5, 1 and 2 wt.%. UHMWPE- TiO2 composites manufactured by solution gelation method. Decalin was used as a solvent for UHMWPE. Recent studies showed that the addition of reinforcement particles in polymer matrix result in enhancement of mechanical properties [5]. Scanning Electron Microscope (SEM) and EDS analysis techniques reviled that TiO2 particles were distributed homogenously in the UHMWPE matrix. The melting temperature Tm and the enthalpy of fusion (ΔHf) were measured by the DSC method. Calculated crystallinity value of 24% for UHMWPE increased to 47% with the addition of TiO2 particles. The presence of C-H2, C-H and C-O bonds and type were verified by FTIR analysis. Mechanical properties of composites were analyzed with tensile tester. Increase in TiO2 content from 0% to 2wt.% increased the 67% young modulus of composite which is much more than the pure UHMWPE used for total joint replacements in the literature [5].