This study is focused to the effects of plastic working on the fatigue strength of Ti-6Al-4V alloy with notch. In general, the fatigue strength of plastic worked specimen is higher than that of non-worked one. However, the potential of hardening ability of Ti-6Al-4V alloy is very limited. Accordingly, the effect of work hardening on fatigue strength about this material is very small. In addition, the surface of the worked part becomes rougher with increasing plastic deformed value and the fatigue cracks initiate at this part. Consequently, the fatigue limit of the plastic worked specimen is lower than that of the non-plastic-worked one.