Interpretations of fracture toughness characteristics, as measured by various test procedures, for solutions of general engineering problems, are presented for structural titanium alloys.Analytical procedures evolved from fracture mechanics theory are used for quantitative interpretations of engineering fracture toughness tests.The procedural simplicity of the engineering tests coupled with the analytical capabilities of fracture mechanics theory provides for a significant advancement in failure-safe design procedures for titanium alloys covering the full range of strength levels.Interpretative procedures are evolved from correlations of KIc with Dynamic Tear (DT) and Charpy-V notch (Cv) energy.An Optimum Material Trend Line (OMTL) diagram is developed for titanium alloys which summarizes all the DT fracture toughness data and is additionally indexed according to the KIc and Cv, correlation plots.OMTL limit curves are shown for the best and normally expected grades of material for the strength level.