The results of a recent study of the fatigue crack growth in a new class of niobium aluminide (Nb3Al) intermetallics alloyed with various levels of Ti are presented. The alloys studied have the following nominal compositions (note that all compositions are quoted in atomic &): Nb-15Al-10Ti(10Ti alloy), Nb-15Al-25Ti(25Ti alloy), Nb-15Al-40Ti(40Ti alloy) and Nb-12.5A1–41Ti-1.5Mo(41Ti alloy). Fatigue crack growth behavior was studied at room-temperature in all the alloys. Fracture mechanisms were determined by inspection of SEM images of fracture surfaces. Faceted cleavage fracture modes were apparent on the lOTi and 25Ti alloys. The 40Ti and 41Ti alloys exhibited clear evidence of ductile dimpled fracture. The ductile 40Ti and 41Ti alloys are shown to have comparable or better fatigue crack growth resistance than mill annealed Ti-6A1–4V. The effects of crack orientation (relative to elongated grains) on the fatigue crack growth behavior of the 41Ti alloy are also discussed.