Fatigue behavior of hybrid welded joints made of titanium alloy grade 5 (Ti-6Al-4V) has been experimentally investigated. Fatigue data have been analyzed in order to study the influence of cord geometry (as-welded specimens have been compared with erased ones). Fatigue curves have been plotted both in terms of local strain amplitude and nominal stress amplitude. According to the WELFARE method, electrical strain gages have been bonded at the weld toe in order to measure the local strain amplitude as representative parameter of fatigue damage. Experimental results show that the fatigue strength is highly dependent from microstructural variations, and especially from defects and imperfections due to the welding process. Titanium welded joints fatigue strength is much more higher than classical materials such as steel, but internal porosity and external macro-defects, like fused material drops, definitely decrease mechanical characteristics and the fatigue life of titanium welded joints.