Abstract: The effects of hydrogen on the mechanical properties at room temperature of a Ti3Al based alloy Ti-24Al-11Nb-3V-1Mo have been investigated. The results show a parabolic rate relationship between the average hydrogen concentration of the alloy at constant temperature and charging time. The mechanical properties (ultimate bending strength and deflection) decrease with increasing hydrogen content in the alloy. The fractographic feature indicates that the decrease of the mechanical properties is due to the crack nucleation and propagation at the hydride Ti3AIH