Fundamental research reveals that the addition of both sulfur and rare earth metals to pure titanium and titanium alloys produces sulfide inclusions and improves the machinability. Sulfur decreases cutting forces and improve tool lives in drilling and turning as the content increases. Rare earth metals also decrease cutting forces and improve tool lives in drilling. However, there is a proper content of rare earth metals to reach the best tool life in turning.Based on the fundamental research, free-machining pure titanium and free-machining titanium alloys were developed. These new grades have good machinability including high productivity and good chip breakability. The mechanical properties, fatigue strength and corrosion resistance of the free-machining grades are almost the same as those of basic grades.