Reaction-bonded aluminium niobate-based composites with tailored microstructures were fabricated through controlled nucleation and growth of AlNbO4 needle-like grains. Using heating rates of 0.5 to >160 degrees C min(-1), the effects of heat-up period on microstructure development, and the volume content, grain-size distribution as well as aspect ratio of AlNbO4 grains has been investigated. The morphology of the final microstructure is principally determined by the grain growth during heat-up. Equiaxed to elongated grains were obtained by using different heating rates and thermal ageing at 1320 degrees C in air. SEM observations revealed that increasing the heating rate promotes the development of large and homogeneously distributed needle-like grains. The results presented show that tailoring of final AlNbO4 microstructures become possible by the control of heating rate.