Purpose: To evaluate the mechanical properties and biologic response of single-phase Ti-Zr alloys cast in higher-purity casting conditions, with comprehensive compositions (from 10 to 90 mol% of Zr). Materials and Methods: The mechanical properties and in vitro biologic response with proportional increase of Zr to Ti-Zr alloy composition were assessed. Tensile strength, surface hardness, and Young's modulus were examined. The in vitro cell response of the alloys was also tested with mouse osteoblast cells. Results: Analyses of mechanical tests demonstrated improved strength and reduced Young's modulus on this binary alloy system. In vitro cell culture studies with osteogenic MCT3T-E1 cells exhibited the highest attachment rate with the largest and more mature cells on Ti10Zr, instead of commercially pure Ti, whereas a significantly lower cell attachment rate and delayed alkaline phosphatase-specific activity (ALP) differentiation were detected on Ti50Zr. Conclusion: The results revealed that the composition did have an impact on the in vitro biologic response. Ti-Zr alloys with 50-50 mol% composition had a decreased biologic response, although the mechanical properties improved. The overall highest strength was Ti with 30 mol% Zr without significant decrease of biologic response. Keywords: alloy composition, biologic response, dental implant material, mechanical property, titaniumzirconium alloy