Titanium-disilicide was formed by deposition of high purity titanium (99.99%) on a silicon (111) wafer in ultra-high vacuum and in-situ annealing. The deposition was monitered using reflection high energy electron diffraction as a function of deposited titanium thickness. The epitaxial growth of TiSi2 on Si (111) by deposition of 200 monolayer thick titanium on the clean surface of silicon and annealing at 750-degrees-C for 1 h was identified using a transmission electron microscope. Almost the whole area of the silicide layer was revealed as epitaxial TiSi2 with C54 structure. Cross-sectional high resolution images of the sample showed that the TiSi2/Si interface is incoherent. Three kinds of orientation relationships were identified as (111BAR)TiSi2 parallel-to (220BAR)Si, [123BAR]TiSi2 parallel-to [112BAR]Si, (311BAR)TiSi2 parallel-to (002)Si, [136BAR] TiSi2 parallel-to [110BAR]Si and (022)TiSi2 parallel-to (200)Si, [233BAR]TiSi2 parallel-to [011BAR]Si with misorientations of 6-degrees, 2-degrees and 14.74-degrees, respectively.