The alkali niobates MNbO₃ (M = Li, Na, K) were synthesized using a matrix-mediated synthesis strategy. Integration of the metal ions inside (a) a sugar - PVA (D-sucrose/polyvinylalkohol) matrix, (b) activated carbon, and (c) mesoporous cross-linked polystyrene is used for the space-confined formation and crystallization of the compounds. Calcination of the amorphous precursors causes crystallization of the niobates and disintegration of the matrix. The resulting nanopowders were investigated using wide-angle X-ray diffraction (WAXS), and pure phases were detected using the different matrixes. Scanning electron microscopy (SEM) reveals the uniform size and morphology of the particles. According to nitrogen physisorption isotherms of the powders, specific surface areas up to 188 m² g^-1 can be obtained. The applicability of the three different methods is discussed.