The design and development of novel titanium alloys for structural and biomedical applications require reliable thermodynamic and kinetic databases. In this study, diffusion behaviors of six Ti-X (X = Cr, Hf, Mo, Nb, V, Zr) binary systems were systematically investigated at temperatures from 800 to 1200 A degrees C using a set of five Ti-TiAl-Cr-Hf-Mo-Nb-V-Zr diffusion multiples. Concentration profiles of the six Ti-X binary systems were collected from binary regions of the diffusion multiples using electron probe microanalysis (EPMA). Both interdiffusion and impurity (dilute) diffusion coefficients in the Ti-rich bcc phase of these systems were extracted from the concentration profiles using the forward-simulation method. Twenty impurity diffusion coefficients of all the six elements in bcc Ti as well as Ti in bcc Zr at different temperatures obtained from this study are in excellent agreement with the literature data. The interdiffusion coefficients obtained from this study are also in good agreement with previous literature results. The large amount of new experimental data obtained from this study will be essential for establishing the mobility databases for the design and development of advanced titanium alloys.