We have observed very large tunneling magnetoresistance (TMR) in Ga1-xMnxAs/AlAs/Ga1-xMnxAs ferromagnetic semiconductor tunnel junctions. A TMR ratio as high as 75% was obtained in a junction with a thin (1.5 nm) AlAs tunnel barrier when the magnetic field was applied along the  axis in the film plane. The TMR ratio decreased when the applied magnetic field direction was along the [11¯0] and . This anisotropic TMR was found to be explained by the single-domain theory assuming cubic magnetic anisotropy with the easy axis of <100>, which is induced by the zincblende-type Ga1-xMnxAs crystal structure. © 2001 American Institute of Physics.